Technical best management practices are the dominant approach promoted to mitigate agriculture’s significant contributions to environmental degradation. Yet very few social science studies have examined how farmers actually use these practices. This study focuses on the outcomes of farmers’ technical best management practice adoption related to synthetic nitrogen fertilizer management in the context of Midwestern corn agriculture in the United States. Moving beyond predicting the adoption of nitrogen best management practices, I use structural equation modeling and data from a sample (...) of over 2500 farmers to analyze how the number of growing season applications a farmer uses influences the rate at which synthetic nitrogen is applied at the field-level. I find that each additional application of N during the growing season is associated with an average increase of 2.4 kg/ha in farmers’ average N application rate. This result counters expectation for the outcome of this practice and may suggest that structural pressures are leading farmers to use additional growing season applications to ensure sufficiently high N rates, rather than allowing them to reduce rates. I conclude by discussing the implication of this study for future research and policy. (shrink)

Globally, mortality and fertility rates generally fall as resource abundance increases. This pattern represents an evolutionary paradox insofar as resource-rich ecological contexts can support higher numbers of offspring, a component of biological fitness. This paradox has not been resolved, in part because the relationships between fertility, life history strategies, reproductive behavior, and socioeconomic conditions are complex and cultural-historically contingent. We aim to understand how we might make sense of this paradox in the specific context of late-twentieth-century, mid–demographic transition (...) Chile. We use distribution-specific generalized linear models to analyze associations between fertility-related life-history traits—number of offspring, ages at first and last reproduction, average interbirth interval, and average number of live births per reproductive span year—and socioeconomic position (SEP) using data from a cohort of 6,802 Chilean women born between 1961 and 1970. We show that Chilean women of higher SEP have shorter average interbirth intervals, more births per reproductive span year, later age at first reproduction, earlier ages at last reproduction, and, ultimately, fewer children than women of lower SEP. Chilean women of higher SEP consolidate childbearing over a relatively short time span in the middle of their reproductive careers, whereas women of lower SEP tend to reproduce over the entirety of their reproductive lifespans. These patterns may indicate that different SEP groups follow different pathways toward declining fertility during the demographic transition, reflecting different life-history trade-offs in the process. (shrink)

Demographic transition faced by modern economies, including China, are among the most important long-term socio-economic challenges. In 2022, China observed its population decline for the first time since the early 1960s. The low fertility rate was of critical importance. The unprecedented one-child policy is quite commonly indicated as the main reason for the low fertility rate. However, the departure from this restrictive policy and the actions introduced under the two-child policy implemented from 2016, and then the (...) three-child policy from mid-2021, have not brought an improvement in fertility rates. The aim of the paper is to answer the following research questions: Should the decline and persistent low fertility rate in China be attributed solely or mainly to the unprecedented one-child policy, which was in force for over three decades? Fertility transition in China is the effect of several factors and depends largely on the studied period. In the 1970s and 1980s, the government’s family policy was a key determinant of the decline in fertility. However, contrary to the prevailing belief about the determining influence of the one-child policy, the first stage of the implementation of the birth control policy, the Wan, Xi, Shao program, had a greater impact. Since the 1990s, the low fertility rate has been mainly explained by the extraordinary socio-economic changes and rapidly increasing prosperity of the Chinese people. Since the beginning of the 21st century, cultural changes resulting mainly from the integration of the Chinese economy with the global system have been crucial. Cultural changes have affected reproductive behaviour, marriage patterns, marriage postponement, birth postponement, fertility, and family size in Chinese society, which is observed below-replacement fertility. China’s demographic future depends on the fertility trajectory. However, due to the size of the population, but also the position of the Chinese economy in the global economic system, Chinese demographic transition may also bring significant consequences for the global economy. (shrink)

The decline in the number of legitimate live births in England and Wales from the peak in 1964 has been partitioned into components due to changes in fertility rates, components due to changes in the composition of the population exposed to risk, and an interaction component. Fertility rates specific for age of mother at birth of child, duration of marriage, parity and age of mother at marriage were considered but in all cases it was found that the decline (...) was not as great as the change in fertility rates implied. This was due to increases in the number of births due to changes in the composition of the population exposed to risk. (shrink)

In the USA, one child in 285 children is diagnosed with cancer every year, but thanks to improvements in medicine, the survival rate has reached 80%. However, cancer treatments, such as chemotherapy and radiation, are likely to affect their fertility later in life, limiting their ability to conceive. To reduce this risk, ovarian tissue cryopreservation is a surgical procedure that allows the ovarian tissue to be retrieved and cryopreserved in order to be reimplanted back into the abdomen and (...) restore ovarian function in children who become infertile due to gonadotoxic treatments. A case study published in 2014 offered recommendations to help assess whether such a procedure should be offered to female patients who have not yet entered puberty. This paper will investigate whether, in light of more recent and updated literature, their recommendations may need to be revised. (shrink)

This article explores the background to the conclusive drop in Irish fertility rates over the last two decades, from a total fertility rate of 3.55 in 1975 to 1.87 in 1995. This steep decline marks the end of Ireland's position as demographic outlier in Europe, which has proved a compelling topic of investigation for demographers. The decline also marks the end of a society which was characterized by an ideology of largely rural values which placed stringent restrictions (...) on women in order to secure a vision of society which saw the family as its cornerstone. The article analyses the collective impact of women's battles for personal autonomy which have brought about dramatic changes in public policies about contraception, abortion and divorce, changes which have consistently lagged behind these dramatic shifts in fertility. (shrink)

Our objective is to test an optimality model of human fertility that specifies the behavioral requirements for fitness maximization in order (a) to determine whether current behavior does maximize fitness and, if not, (b) to use the specific nature of the behavioral deviations from fitness maximization towards the development of models of evolved proximate mechanisms that may have maximized fitness in the past but lead to deviations under present conditions. To test the model we use data from a representative (...) sample of 7,107 men living in Albuquerque, New Mexico, between 1990 and 1993. The model we test proposes that low fertility in modern settings maximizes number of grandchildren as a result of a trade-off between parental fertility and next generation fertility. Results do not show the optimization, although the data do reveal a trade-off between parental fertility and offspring education and income.We propose that two characteristics of modern economies have led to a period of sustained fertility reduction and to a corresponding lack of association between income and fertility. The first is the direct link between costs of investment and wage rates due to the forces of supply and demand for labor in competitive economies. The second is the increasing emphasis on cumulative knowledge, skills, and technologies in the production of resources. Together they produce historically novel conditions. These two features of modern economies may interact with evolved psychological and physiological mechanisms governing fertility and parental investment to produce behavior that maximizes the economic productivity of lineages at the expense of fitness. If cognitive processes evolved to track diminishing returns to parental investment and if physiological processes evolved to regulate fertility in response to nutritional state and patterns of breast feeding, we might expect non-adaptive responses when returns from parental investment do not diminish until extremely high levels are reached. With high economic payoffs from parental investment, people have begun to exercise cognitive regulation of fertility through contraception and family planning practices. Those cognitive processes maynot have evolved to handle fitness trade-offs between fertility and parental investment. (shrink)

What are the prospects for using population policy as tool to reduce carbon emissions? In this paper, we review evidence from population science, in order to inform debates in population ethics that, so far, have largely taken place within the academic philosophy literature. In particular, we ask whether fertility policy is likely to have a large effect on carbon emissions, and therefore on temperature change. Our answer is no. Prospects for a policy of fertility-reduction-as-climate-mitigation are limited by population (...) momentum, a demographic factor that limits possible variation in the size of the population, even if fertility rates change very quickly. In particular, a hypothetical policy that instantaneously changed fertility and mortality rates to replacement levels would nevertheless result in a population of over 9 billion people in 2060. We use a leading climate-economy model to project the consequence of such a hypothetical policy for climate change. As a standalone mitigation policy, such a hypothetical change in the size of the future population-much too large to be implementable by any foreseeable government programme-would reduce peak temperature change only to 6.4°C, relative to 7.1°C under the most likely population path. Therefore, fertility reduction is unlikely to be an adequate core approach to climate mitigation. (shrink)

SummaryIntense, sustained nursing lengthens inter-birth intervals and is causally linked with low natural fertility. However, in traditional settings, the effects of such nursing on fertility are difficult to disentangle from those of nutrition. Results from an prospective, direct observational study of reproductive function in well-nourished Amele women who nurse intensively and persistently but who also have high fertility are here presented. Endocrine measures show that ovarian activity resumes by median 11·0 months postpartum. Median duration of postpartum amenorrhoea (...) is 11·3 months, time to next conception is 19·0 months, and the inter-birth interval is 28·0 months. Average life time fertility is 6·8. High fertility in Amele women is due both to refractoriness of reproductive function to suckling stimuli, and to maintenance of equivalent age-specific fertility rates across the reproductive life span. (shrink)

The right to conceive and bear children has been protected both in law and in policy. Human society has from its earliest time valued children and defended procreation as a basic right.Modern health technology offers the possibility of conception to the estimated 2.5 million infertile couples who may wish to have children. For these persons, infertility treatment offers the hope of having children, an activity deemed basic and essential in human society.In general, the state has been reluctant to directly interfere (...) in the reproductive decisions of individuals. However, the state may act to increase or reduce access to reproductive services in a variety of ways. For example, recent legislation regulating fertility clinics affects the distribution of assisted reproductive technology in the United States. The purpose of this paper is to describe this legislation, project its probable effects on the distribution of ART services, and analyze these effects based on distributive theories of justice. (shrink)

With the cure rate for many pediatric malignancies now between 70% and 90%, infertility becomes an increasingly important issue. Strategies for preserving fertility in girls and adolescent women occur in two distinct phases. The first phase includes oophorectomy and cryopreservation of ovarian cortex slices or individual oocytes; ultrasound-guided needle aspiration of oocytes, with or without in vitro maturation, followed by cryopreservation; and ovarian autografting to a distant site. The second phase occurs if the woman chooses to pursue pregnancy, (...) and includes IVM of the oocytes, followed by in vitro fertilization and transfer of any created embryos to the woman's uterus. For ovarian autografting, the woman would undergo menotropin ovarian stimulation and retrieval of matured oocytes. The ethical challenges with each of these phases are many of fertility preservation and include issues of informed choice. The lack of proven benefit with these strategies and the associated potential physical and psychological harms require careful attention to the key elements of informed choice, which include decisional capacity, disclosure, understanding and voluntariness, and to the benefits of in-depth counseling to promote free and informed choice at a time that is emotionally difficult for the decision makers. (shrink)

Sustaining soil fertility is essential to the prosperity of many households in the mid-hills of Nepal, but there are concerns that the breakdown of the traditional linkages between forest, livestock, and cropping systems is adversely affecting fertility. This study used triangulated data from surveys of households, discussion groups, and key informants in 16 wards in eastern and western Nepal to determine the existing practices for soil fertility management, the extent of such practices, and the perception of the (...) direction of changes in soil fertility. The two principal practices for maintaining soil fertility were the application of farmyard manure (FYM) and of chemical fertilizer (mainly urea and diammonium phosphate). Green manuring, in-situ manuring, slicing terrace risers, and burning plant residues are rarely practiced. FYM usage was variable with more generally applied to khet land (average 6053 kg fresh weight manure ha−1) than to bari land (average 4185 kg fresh weight manure ha−1) with manure from goats and poultry preferred above that from cows and buffaloes. Almost all households (98%) apply urea to khet land and 87% to bari land, with 45% applying diammonium phosphate to both types of land. Application rates and timings of applications varied considerably both within and between wards suggesting poor knowledge transfer between the research and farming communities. The benefits of chemical fertilizers in terms of ease of application and transportation in comparison with FYM, were perceived to outweigh the widely reported detrimental hardening of soil associated with their continued usage. Among key informants, FYM applied in conjunction with chemical fertilizer was the most popular amendment, with FYM alone preferred more than chemical fertilizer alone – probably because of the latter’s long-term detrimental effects. Key informant and householder surveys differed in their perception of fertility changes in the last decade probably because of differences in age and site-specific knowledge. All key informants felt that fertility had declined but among households, only about 40% perceived a decline with the remainder about evenly divided between no change and an increase. Householders with small landholdings (< 0.5 ha) were more likely to perceive increasing soil fertility while those with larger landholdings (> 2 ha) were more likely to perceive declining fertility. Perceived changes in soil fertility were not related to food self-sufficiency. The reasons for the slow spread of new technologies within wards and the poor understanding of optimal use of chemical fertilizers in conjunction with improved quality FYM may repay further investigation in terms of sustaining soil fertility in this region. (shrink)

SummaryThe Gainj of highland Papua New Guinea do not use contraception but have a total fertility rate of only 4·3 live births per woman, one of the lowest ever recorded in a natural fertility setting. From an analysis of cross-sectional demographic and endocrinological data, the causes of low reproductive output have been identified in women of this population as: late menarche and marriage, a long interval between marriage and first birth, a high probability of widowhood at later (...) reproductive ages, low effective fecundability and prolonged lactational amenorrhoea. These are combined with near-universal marriage, a low prevalence of primary sterility and a pattern of onset of secondary sterility similar to that found in other populations. Of all the factors limiting fertility, by far the most important are those involved in birth spacing, especially lactational amenorrhoea. (shrink)

Male provisioning ability may have evolved as a “good dad” indicator through sexual selection, whereas male creativity may have evolved partly as a “good genes” indicator. If so, women near peak fertility (midcycle) should prefer creativity over wealth, especially in short-term mating. Forty-one normally cycling women read vignettes describing creative but poor men vs. uncreative but rich men. Women’s estimated fertility predicted their short-term (but not long-term) preference for creativity over wealth, in both their desirability ratings of individual (...) men (r=.40, p<.01) and their forced-choice decisions between men (r=.46, p<.01). These preliminary results are consistent with the view that creativity evolved at least partly as a good genes indicator through mate choice. (shrink)

The objectives of this article are, first, to provide improved estimates of recent fertility levels and trends in Nepal and, second, to analyse the components of fertility change. The analysis is based on data from Nepals education. The own-children estimates for the whole country indicate that the TFR declined from 4·96 to 4·69 births per woman between the 3-year period preceding the 1996 survey and the 3-year period preceding the 2001 survey. About three-quarters of the decline stems from (...) reductions in age-specific marital fertility rates and about one-quarter from changes in age-specific proportions currently married. Further decomposition of the decline in marital fertility, as measured by births per currently married woman during the 5-year period before each survey, indicates that almost half of the decline in marital fertility is accounted for by changes in population composition by ecological region, development region, urban/rural residence, education, age at first cohabitation with husband, time elapsed since first cohabitation, number of living children at the start of the 5-year period and media exposure. With these variables controlled, another one-third of the decline is accounted for by increase in the proportion sterilized at the start of the 5-year period before each survey. (shrink)

In El Salvador from 1978 to 1988, contraceptive use among married women 15–44 years of age increased from 34% to 47%, and the total fertility rate declined from 6·3 to 4·6 children per woman. Most of this change took place from 1978 to 1985. Sterilization is the most prevalent method used, but nearly one-half of the women who are sterilized did not use any contraception before their operation. Few young couples use reversible methods of contraception to space births (...) or delay the start of childbearing. On average, women wait 8 years after marriage and have nearly three children before they use contraception. (shrink)

This introduction to fictional “fertility dystopias” presents literary examples of the rapid expansion or collapse of populations through the manipulation of fertility or the fraught inability or decision not to. Additionally, these fictions are periodized with their extraliterary social contexts, revealing roughly three intervals: pronatalism dominant before the 1950s, antinatalism ascendant from the 1950s to the early 1970s, and, beginning in the middle 1970s to the present, contestation between pronatalism and antinatalism. Despite the ascendance of antinatalism, fertility (...) dystopias in the middle interval reveal antinatalist assumptions but with accompanying anxiety rather than complete endorsement. Today, tracking with global variations in local fertility rates and development levels, both antinatalist and pronatalist messages are expressed with equal vigor. (shrink)

SummaryFrom 1996 to 2006, Nepal experienced a substantial fertility decline, with the total fertility rate dropping from 4.6 to 3.1 births per woman. This study examines the associations between progress towards universal primary and secondary schooling and fertility decline in rural Nepal. Several hypotheses regarding mechanisms through which education affects current fertility behaviour are tested, including: the school environment during women's childhood; current availability of schools; knowledge of educational costs; and women's own educational attainment. Data (...) for the analysis come from the 2003–04 Nepal Living Standards Survey, a nationally representative random sample of households, which includes detailed data on fertility, household expenditure, educational attainment, demographic characteristics and the use of social services. Census and administrative data are also used to construct district-level gross enrolment ratios for primary and secondary schools during the women's childhood. Discrete dependent variable modelling techniques are used to estimate the effects of the following variables on the probability of women giving birth in a given year: district-level gross enrolment ratios for primary and secondary schools during women's childhood; having had a child previously in school; women's own educational level; current school availability; and other covariates. Separate models are estimated for the overall sample of rural women of reproductive age, and for parity-specific sub-samples. The results suggest that district-level gross enrolment ratios for secondary schools and, in some instances, having had a previous child enrolled in school are significant determinants of fertility in rural areas. These results are highly independent of women's own educational levels. Overall, the results suggest that, in the rural Nepal context, mass schooling influences the fertility transition through both community- and household-level pathways. (shrink)

Background: Studies of sexual conditioning typically focus on the development of conditioned responses to a stimulus that precedes and has become associated with a sexual unconditioned stimulus (US). Such a sexually conditioned stimulus (CS) provides the opportunity for feed-forward regulation of sexual behavior, which improves the efficiency and effectiveness of the sexual activity. Objective and Design: The present experiments were conducted to provide evidence of such feed-forward regulation of sexual behavior in laboratory studies with domesticated quail by measuring how many (...) fertilized eggs were produced by the female after the sexual encounter. During the conditioning phase, male and female quail received a conditioned stimulus paired with the opportunity to copulate with each other. Results: Sexual conditioning increased the number of eggs that were fertilized as a consequence of copulation, especially if both the male and the female were exposed to the sexual CS. This conditioned fertility effect occurred with a range of CS durations and CS types. The conditioned fertility effect also occurred in situations involving sexual competition. When two males copulated with the same female, DNA fingerprinting showed that the male whose sexual encounter was signaled by a sexual CS was responsible for most of the resulting offspring. Sexual conditioning also reduced the first-male disadvantage in fertilization that occurs when two males copulate with the same female separated by several hours. Another significant finding was that sexual conditioning attenuated the usual drop in fertilization rate that occurs when the same male copulates with two females in succession. Conclusion: These results show that sexual conditioning increases the number of offspring that are produced in both isolated male-female encounters and in situations that involve two males copulating with the same female or one male copulating with more than one female. By increasing fertilization rates, sexual conditioning can alter genetic transmission across generations and shape evolutionary change. Keywords: sexual conditioning; sexual learning; conditioned fertility; sexual competition; quail; pavlovian conditioning (Published: 15 March 2012) Citation: Socioaffective Neuroscience & Psychology 2012, 2 : 17333 - DOI: 10.3402/snp.v2i0.17333. (shrink)

In the literature investigating the long history of appeals to ‘nature’, in its multiple meanings, for rules of conduct or justification of social order, little attention has been paid to a long-standing tradition in which medical and physiological arguments merged into moral and social ones. A host of medical authors, biologists, social writers and philosophers assumed that nature spoke its moral language not only in its general economy, but also within and through the body. This is why, for instance, many (...) critics of Malthus argued that physiological self-regulating mechanisms ensured a spontaneous adaptation of fertility to the circumstances. Beliefs in a beneficent economy of nature persisted when Providence was replaced by evolution. To some, they provided reasons for hope even when others worried about ‘unfit’ members of society increasing at a quicker rate than ‘fit’ ones. The nerves gradually replaced food and blood as moral mediators between society and the body. When faith in bio-social progress was shaken by degeneration theories, and fin de siècle anxiety concerned underpopulation rather than overpopulation, not an insignificant proportion of those who emphasised the bad effects of modern civilisation resorted to ideas and arguments based on a view of the body in which physiology and morality worked together. A common language and common assumptions linked the Kulturpessimisten to their optimistic eighteenth-century colleagues, in spite of their different forecasts. The present paper traces continuities and discontinuities in the operation of a persistent set of interrelated ideas and assumptions on the coalescence of the physiological and the moral across disciplines and contexts. (shrink)

In the literature investigating the long history of appeals to ‘nature’, in its multiple meanings, for rules of conduct or justification of social order, little attention has been paid to a long-standing tradition in which medical and physiological arguments merged into moral and social ones. A host of medical authors, biologists, social writers and philosophers assumed that nature spoke its moral language not only in its general economy, but also within and through the body. This is why, for instance, many (...) critics of Malthus argued that physiological self-regulating mechanisms ensured a spontaneous adaptation of fertility to the circumstances. Beliefs in a beneficent economy of nature persisted when Providence was replaced by evolution. To some, they provided reasons for hope even when others worried about ‘unfit’ members of society increasing at a quicker rate than ‘fit’ ones. The nerves gradually replaced food and blood as moral mediators between society and the body. When faith in bio-social progress was shaken by degeneration theories, and fin de siècle anxiety concerned underpopulation rather than overpopulation, not an insignificant proportion of those who emphasised the bad effects of modern civilisation resorted to ideas and arguments based on a view of the body in which physiology and morality worked together. A common language and common assumptions linked the Kulturpessimisten to their optimistic eighteenth-century colleagues, in spite of their different forecasts. The present paper traces continuities and discontinuities in the operation of a persistent set of interrelated ideas and assumptions on the coalescence of the physiological and the moral across disciplines and contexts. (shrink)

In the literature investigating the long history of appeals to ‘nature’, in its multiple meanings, for rules of conduct or justification of social order, little attention has been paid to a long-standing tradition in which medical and physiological arguments merged into moral and social ones. A host of medical authors, biologists, social writers and philosophers assumed that nature spoke its moral language not only in its general economy, but also within and through the body. This is why, for instance, many (...) critics of Malthus argued that physiological self-regulating mechanisms ensured a spontaneous adaptation of fertility to the circumstances. Beliefs in a beneficent economy of nature persisted when Providence was replaced by evolution. To some, they provided reasons for hope even when others worried about ‘unfit’ members of society increasing at a quicker rate than ‘fit’ ones. The nerves gradually replaced food and blood as moral mediators between society and the body. When faith in bio-social progress was shaken by degeneration theories, and fin de siècle anxiety concerned underpopulation rather than overpopulation, not an insignificant proportion of those who emphasised the bad effects of modern civilisation resorted to ideas and arguments based on a view of the body in which physiology and morality worked together. A common language and common assumptions linked the Kulturpessimisten to their optimistic eighteenth-century colleagues, in spite of their different forecasts. The present paper traces continuities and discontinuities in the operation of a persistent set of interrelated ideas and assumptions on the coalescence of the physiological and the moral across disciplines and contexts. (shrink)

The performance of population programmes suggests that even the more successful ones have acceptance rates that are only a fifth or so of what is needed to reduce population growth rates to the 1% a year that permits significant improvements in income per head. It is also clear that no programmes use bonuses at anything approaching the monetary values per recipient that are justifiable. There is no guarantee that such bonuses will produce the number of acceptors that are needed, but (...) it is fairly evident that without larger bonuses there will not be enough acceptors. (shrink)

Selective reproductive technologies, such as preimplantation genetic diagnosis, enable enhanced clinical success rates, create reproductive choices, and produce new commercial opportunities. Drawing upon empirical material acquired during a ten-month period in 2016, this study uses a total of twenty-two in-depth interviews with doctors, CEOs, clinical directors, marketing directors, patient counselors, and embryologists to discuss how traveling for the SRT of gender selection for nonmedical reasons is mediated by fertility clinics and clinicians in Dubai. Multimodal analysis was used to analyze (...) the clinical websites’ key rhetorical and visual features. Meanwhile, interviews and observational studies highlighted the context within which gender selection takes place. Findings revealed that gender selection is promoted as a form of “enhancement” and “family balance,” which, when combined with the ways that Dubai is assembled as a sensory tourist destination, routinize SRTs and lead to an understanding of gender selection as not merely an individualized reproductive journey but an optimization of the family unit. (shrink)

This paper explores the experiences of infertile women who occupy a liminal space in society, and argues that the fertility clinic served as a space to tolerate women's experiences of liminality. It provided not only rituals aimed at transition to pregnancy, but also a space where women's liminal experiences, which are caused by the existential chaos of infertility, could be tolerated. The British experience seemed to differ from the American one identified in the literature, where self‐management and peer group (...) support are described as strategies used by infertile women to manage infertility. The British women in this study did not appear to draw so much on self‐management or peer group support to deal with their experiences of infertility. They appeared to be isolated in their experience. The clinic thus provided a space in which recognition was given to their intensely private experiences of difference from those in the outside fertile world and allowed them to manage these socially unacceptable, culturally taboo and invisible experiences. However, because of its very limited success rate in enabling women to become pregnant, rather than facilitating the transition of status from infertile to fertile woman, the clinic also served to reinforce the liminal experiences of those women who remained infertile. Inadvertently, the clinic offered a way of being in limbo while at the same time reinforcing the liminal experiences of women. (shrink)

In vitro fertilization is now a well-established practice in the field of assisted reproduction. In 1995, over 41,000 IVF cycles were done in the United States, at a cost of more than $300 million. The overall success rate has risen to 22.8 deliveries per 100 egg-retrieval procedures. As the field has matured, the attention of policy-makers has shifted from questions about the ethical and legal status of human embryos to concerns about providing access and protecting consumers.Three such concerns have (...) emerged. One is the danger that IVF programs will disseminate misleading information about their success rates in order to attract patients. This problem, however, may be alleviated by the publication in late 1997 of the first of annual national and clinic specific reports, based on randomly audited data, by the Centers for Disease Control and Prevention, the American Society of Reproductive Medicine, the Society for Assisted Reproductive Technology, and RESOLVE, pursuant to the federal 1992 Fertility Clinic Success Rate and Laboratory Certification Act. (shrink)

In vitro fertilization is now a well-established practice in the field of assisted reproduction. In 1995, over 41,000 IVF cycles were done in the United States, at a cost of more than $300 million. The overall success rate has risen to 22.8 deliveries per 100 egg-retrieval procedures. As the field has matured, the attention of policy-makers has shifted from questions about the ethical and legal status of human embryos to concerns about providing access and protecting consumers.Three such concerns have (...) emerged. One is the danger that IVF programs will disseminate misleading information about their success rates in order to attract patients. This problem, however, may be alleviated by the publication in late 1997 of the first of annual national and clinic specific reports, based on randomly audited data, by the Centers for Disease Control and Prevention, the American Society of Reproductive Medicine, the Society for Assisted Reproductive Technology, and RESOLVE, pursuant to the federal 1992 Fertility Clinic Success Rate and Laboratory Certification Act. (shrink)

Food insecurity and the loss of soil nutrients and productive capacity in Africa are serious problems in light of the rapidly growing African population. In semi-arid central Tanzania currently practiced traditional crop production systems are no longer adaptive. Organic crop production methods alone, while having the capacity to enable food security, are not feasible for these small-scale farmers because of the extra land, skill, resources, and 5–7 years needed to benefit from them—particularly for maize. Maize, grown by 94 % of (...) farmers, has substantial nitrogen needs. The most practical ways of satisfying maize nutrient needs is via integrated soil fertility management, a combination of organic and Green Revolution methods. Maize has been shown in research to outyield the indigenous crops millet and sorghum in nearly all situations including drought. Conservation Agriculture (CA) in Africa has two main categories—organic and herbicide-mediated. The organic version of CA, despite years of promotion, has had a low rate of adoption. Herbicide-mediated zero tillage CA via backpack sprayer can substantially increase conventional maize yields while at the same time nearly eliminating erosion and increasing rainwater capture up to fivefold. Glyphosate herbicide is a non-proprietary product produced in Africa and approved for small farm use. The systemic nature of glyphosate allows the killing of perennial grasses that would otherwise need deep plowing to kill. The rooted weed residues protect the soil from erosion. The risks of glyphosate use are substantially outweighed by the benefits of increased food security and crop system sustainability. (shrink)

The birth rates per 1000 married females of specified ages and durations of marriage generally attained their post-war maxima in 19463000 and (b) the cumulative fertility up to 5 or 10 years of marriage duration of later cohorts was considerably higher (13–40% higher) than that of earlier cohorts. These facts, and similar ones for Australia covering a wider period (Basavarajappa, 1964), are thought to suggest that the total fertility of cohorts who have not yet completed their childbearing might (...) not be far outside the limits of 2500 and 3000. (shrink)

Using nationally representative data, it is shown that marital unions are relatively stable in Nigeria. Remarriage rates are high so little time is lost between unions. Consequently, the fertility of women who have experienced marital disruption is only slightly lower than for those in stable unions. Their slightly lower parity may be a function of a high incidence of reproductive impairment, which is a major reason for divorce and separation in Nigeria.

The percentage of accidental pregnancies, the Pearl pregnancy rate and the life-table method have all been used to study the effectiveness of contraception in Belgium, using data from the Second National Fertility Survey (1971), which covered 3397 Belgian women in the age group 30–34 years. Though all three methods yield generally similar results, it is only by using the third method that we can obtain in an optimum way changes in contraceptive effectiveness by birth order and birth interval.

It is widely recognized that mineral fertilizers must play an important part in improving agricultural productivity in western Kenyan farming systems. This paper suggests that for this goal to be realized, farmers’ knowledge must be strengthened to improve their understanding of fertilizers and their use. We analyzed smallholder knowledge of fertilizers and nutrient management, and draw practical lessons from empirical collective fertilizer-response experiments. Data were gathered from the collective fertilizer-response trials, through focus group discussions, by participant observation, and via in-depth (...) interviews representing 40 households. The collective trials showed that the application of nitrogen (N) or phosphorous (P) alone was insufficient to enhance yields in the study area. The response to P on the trial plots was mainly influenced by incidences of the parasitic Striga weed, by spatial variability or gradients in soil fertility of the experimental plots, and by interactions with N levels. These results inspired farmer to design and conduct experiments to compare crop performance with and without fertilizer, and between types of fertilizers, or responses on different soils. Participating farmers were able to differentiate types of fertilizer, and understood rates of application and the roles of respective fertilizers in nutrient supply. However, notions were broadly generated by unsteady yield responses when fertilizers were used across different fertility gradients, association with high cost (especially if recommended rates were to be applied), association of fertilizer use with hybrids and certain crops, historical factors, among other main aspects. We identified that strengthening fertilizer knowledge must be tailored within existing, albeit imperfect, systems of crop and animal husbandry. Farmers’ perceptions cannot be changed by promoting more fertilizer use alone, but may require a more basic approach that, for example, encourages farmer experimentation and practices to enhance soil properties such as carbon build-up in impoverished local soils. (shrink)

The fall in the birth rate in Australia, from 234 in 1967 is analysed according to various biosocial factors: the age composition of the female population and the age incidence of marriage in relation to it, the timing of births, the size of completed family and the overall effect of the variables.

Faced with declining fertility rates, media in Britain are reacting with anxiety about cultural annihilation. To look at how nationalism inflects concerns over biological and cultural reproduction, the authors analyze coverage of falling fertility and rising immigration in Great Britain in major newspapers in 2000-2. They find pronatalist appeals to be commonand especially directed at women but varying in how women’s duty to the nation is framed. Appeals characterized as begging, lecturing, threatening, and bribing express different relationships between (...) individual interest and the national good and offer positive and negative views of women. The political leanings of specific newspapers affect how they connect biological reproduction to the cultural threat seen in immigration. Even positive views of women as making rational reproductive choices are tainted by alarmist views of immigration as a threat to national survival. (shrink)

Life history theory predicts that greater extrinsic mortality will lead to earlier and higher fertility. To test this prediction, I examine the relationship between life expectancy at birth and several proxies for life history traits (ages at first sex and first marriage, total fertility rate, and ideal number of children), measured for both men and women. Data on sexual behaviors come from the Demographic and Health Surveys (DHS). Two separate samples are analyzed: a cross-sectional sample of 62 (...) countries and a panel sample that includes multiple cross-sectional panels from 48 countries. Multivariate regression analysis is used to control for potential confounding variables. The results provide only partial support for the predictions, with greater support among women than men. However, the prediction is not supported in sub-Saharan African countries, most likely owing to the nonequilibrium conditions observed in sub-Saharan Africa with respect to life expectancy. The applicability of the model to understanding HIV/AIDS risk behaviors is discussed. (shrink)

Contrary to political and philosophical consensus, we argue that the threats posed by climate change justify population engineering, the intentional manipulation of the size and structure of human populations. Specifically, we defend three types of policies aimed at reducing fertility rates: choice enhancement, preference adjustment, and incentivization. While few object to the first type of policy, the latter two are generally rejected because of their potential for coercion or morally objectionable manipulation. We argue that forms of each policy type (...) are pragmatically and morally justified tools for preventing the harms of global climate change. (shrink)

We develop a cultural evolutionary theory of the origins of prosocial religions and apply it to resolve two puzzles in human psychology and cultural history: (1) the rise of large-scale cooperation among strangers and, simultaneously, (2) the spread of prosocial religions in the last 10–12 millennia. We argue that these two developments were importantly linked and mutually energizing. We explain how a package of culturally evolved religious beliefs and practices characterized by increasingly potent, moralizing, supernatural agents, credible displays of faith, (...) and other psychologically active elements conducive to social solidarity promoted high fertility rates and large-scale cooperation with co-religionists, often contributing to success in intergroup competition and conflict. In turn, prosocial religious beliefs and practices spread and aggregated as these successful groups expanded, or were copied by less successful groups. This synthesis is grounded in the idea that although religious beliefs and practices originally arose as nonadaptive by-products of innate cognitive functions, particular cultural variants were then selected for their prosocial effects in a long-term, cultural evolutionary process. This framework (1) reconciles key aspects of the adaptationist and by-product approaches to the origins of religion, (2) explains a variety of empirical observations that have not received adequate attention, and (3) generates novel predictions. Converging lines of evidence drawn from diverse disciplines provide empirical support while at the same time encouraging new research directions and opening up new questions for exploration and debate. (shrink)

This essay introduces, for theological consideration, some recent work in the field of cultural evolutionary theory, specifically the kin‐influence hypothesis. This theory holds that, following the beginnings of industrialization and economic growth, a nation's fertility rate commences a decline, which is further abetted by the consequent and increasing imbalance in the relative influence of kin versus nonkin influences on individuals in favor of the latter. It is further proposed that this process is itself a major independent factor in (...) the emergence of many of the features of what is called modernity, among which is that of secularization. Extending further this work, I argue that, given the historic alignment of family and religious values in Christian nations, a loss of religious belief and practice is, at least in part, the spill over effect of the opposing influence of values emerging from ever more dominant nonfamily social interaction. I conclude with some reflections on possible theological implications. (shrink)

Life history theory aims to explain the relationship between life events, recognizing that the fertility and growth schedules of organisms are dependent on environmental conditions and an organism’s ability to extract resources from its environment. Using models from life history theory, we predict life expectancy to be positively correlated with educational investments and negatively correlated with adolescent reproduction and total fertility rates. Analyses of UN data from 193 countries support these predictions and demonstrate that, although variation is evident (...) across world regions, strong interactions exist among life expectancy, reproductive investments, and educational attainment, and these relationships occur independently of economic pressures and disease burdens. The interactions are strongest, however, in countries with a life expectancy of ≥60 years as these countries tend to have stable economies and a limited HIV/AIDS burden. These findings suggest that policies aimed at influencing education and reproductive decisions should consider environmental characteristics that drive people’s expectations about their longevity. (shrink)

Studies on the association of demographic phenomena and religion have shown that religious institutions and religious identity of individuals can influence in various ways the demographic behavior of followers. This study aimed to identify and analyze possible differences in the fertility behavior and accordance religions among women between 15-49 years old in Brazil, including analyzes from the conversion and the frequency in religious worship and ceremonies. For this data from the National Survey of Demography and Health of Women and (...) Children of 2006 were used. The results suggest that there are differences in fertility rates and types of religions. The same are also observed for those women who were always had the same religion and that changed religion throughout their reproductive period and there are also important differences on the fertility levels and pattern by participation in religious worship and ceremonies. (shrink)

There is something genuinely puzzling about large-scale simplicity emerging in systems that are complex at the small scale. Consider, for example, a population of hares. Clearly, the number of hares at any given time depends on hare fertility rates, the weather, the number of predators, the health of the predators, availability of hare resources, motor vehicle traffic, individual hare locations, colour of individual hares, and so on. Indeed, given the incredibly complexity of the hares’ environment at the small-scale, it (...) is amazing that anything can be said about hare abundances. But not only can we say something about hare abundances, we can formulate equations for hare abundance as a function of time that are remarkably accurate. But most amazing of all is that such equations have very few parameters—in the simplest cases, just the growth rate and an initial population abundance. How can this be? How can we ignore all the small-scale factors when they clearly play major roles in determining abundance? Put somewhat more grandiosely: How is population ecology possible? Of course it’s not just population ecology that exhibits such small-scale complexity and large-scale simplicity. Other important systems include the weather and gases in equilibrium. The examples can easily be multiplied. The general problem is the same: How can seemingly unpredictable and complex microbehaviour of complex systems result in predictable and simple macrobehaviour? Providing an answer to this question is the central task of Michael Strevens’ excellent book Bigger than Chaos : Understanding Complexity through Probability. (shrink)

For most of the vast span of human history, economic growth was all but nonexistent. Then, about two centuries ago, some nations began to emerge from this epoch of economic stagnation, experiencing sustained economic growth that led to significant increases in standards of living and profoundly altered the level and distribution of wealth, population, education, and health across the globe. The question ever since has been--why? This is the first book to put forward a unified theory of economic growth that (...) accounts for the entire growth process, from the dawn of civilization to today. Oded Galor, who founded the field of unified growth theory, identifies the historical and prehistorical forces behind the differential transition timing from stagnation to growth and the emergence of income disparity around the world. Galor shows how the interaction between technological progress and population ultimately raised the importance of education in coping with the rapidly changing technological environment, brought about significant reduction in fertility rates, and enabled some economies to devote greater resources toward a steady increase in per capita income, paving the way for sustained economic growth. Presents a unified theory of economic growth from the dawn of civilization to today Explains the worldwide disparities in living standards and population we see today Provides a comprehensive overview of the three phases of the development process Analyzes the Malthusian theory and its empirical support Examines theories of demographic transition and their empirical significance Explores the interaction between economic development and human evolution. (shrink)

Objective: To determine cryopreservation-induced alterations in the cytoskeleton of metaphase II mouse oocytes and the implications of these alterations in functionality of the cytoskeleton and polyploidy after fertilization.Design: Comparative study.Setting: Clinical and academic research environment at a medical school teaching hospital.Intervention : Oocytes were frozen using a slow-cooling and slow-thawing protocol in 1.5 M dimethyl sulfoxide and 0.2 M sucrose and were analyzed before and after fertilization.Main Outcome Measure : Cytoskeletal alterations, fertilization, and polyploidy rates.Result : When analyzed immediately after (...) thawing, the oocytes displayed dramatic cytoskeletal alterations. Only slight recovery was observed upon removal of the cryoprotectants. However, incubation after thawing of 1 hour at 37oC completely reestablished a normal microfilament and microtubule pattern while partially restoring normal spindle morphology and chromosome alignment. Accordingly, insemination immediately after removal of cryoprotectants resulted in a significantly decreased fertilization rate and aberrant dynamics of cytoskeleton-dependent events, whereas oocytes inseminated after the post-thaw incubation displayed fertilization rates and cytoskeletal dynamics comparable to those in controls. Cryopreservation did not increase polyspermy but significantly increased digyny when the oocytes were inseminated after the post-thaw incubation. All digynic eggs displayed an abnormal spindle remnant in comparison with diploid or polyspermic eggs.Conclusion : A brief period of incubation after thawing allows recovery and positively affects fertilization and cytoskeletal dynamics. Cryopreservation does not impair the functionality of microfilaments and cytoplasmic microtubules during postfertilization events. Our findings suggest that the increased rate of digyny in cryopreserved oocytes may be related to the spindle disorganization, leading to failure in segregation of the chromosomes, rather than to direct malfunction of the microfilaments in polar body formation. (shrink)

In Lesotho, the risk of mother-to-child-transmission (MTCT) of HIV is substantial; women of childbearing age have a high HIV prevalence rate (26·4%), low knowledge of HIV status and a total fertility rate of 3·5 births per woman. An effective means of preventing MTCT is to reduce unwanted fertility. This paper examines the unmet need for contraception to limit and space births among HIV-positive women in Lesotho aged 15–49 years, using the 2004 Lesotho Demographic and Health Survey. (...) HIV-positive women have their need for contraception unmet in almost one-third of cases, and multivariate analysis reveals this unmet need is most likely amongst the poor and amongst those not approving of family planning. Urgent action is needed to lower the level of unmet need and reduce MTCT. A constructive strategy is to improve access to family planning for all women in Lesotho, irrespective of HIV status, and, more specifically, integrate family planning with MTCT prevention and voluntary counselling and testing services. Copyright © Cambridge University Press 2008. (shrink)

Projects of radical life extension have been discussed amongst scientists for years. Some bioethicists express reservations about this endeavor. A common objection appeals to demography: if the human lifespan is dramatically expanded, humanity would face an overpopulation problem. In this essay, the authors reply to this objection. They posit that radical life extension is unlikely to lead to overpopulation because overpopulation is determined more by fertility rates than by longevity, and as a result of the advanced phases of industrialization, (...) fertility rates are likely to be reduced, and therefore, population size would become stable. However, they argue that although overpopulation is not a concern for the foreseeable future, it is still important to acknowledge its potential harms. Finally, they argue that even if overpopulation becomes a problem caused by radical life extension, there are plausible ways to solve it. (shrink)

Populations in developed societies are rapidly aging: fertility rates are at all-time lows while life expectancy creeps ever higher. This is triggering a social crisis in which shrinking youth populations are required to pay for the care and retirements of an aging majority. Some people argue that by investing in the right kinds of lifespan extension technology – the kind that extends the healthy and productive phases of life – we can avoid this crisis (thereby securing a ‘longevity dividend’). (...) This chapter argues that this longevity dividend is unlikely to be paid if lifespan extension coincides with rampant technological unemployment. This does not mean that we should not pursue lifespan extension, but it does mean that the argument in its favor needs to rest on other grounds. After articulating these grounds, the chapter proceeds to consider the implications this has for our vision of the extended life, postwork utopia. It argues that this vision may need to be reconceived and suggests that one plausible reconception involves prioritizing the role of games in the well-lived life. (shrink)

As the world’s most populous country, China is experiencing unprecedented magnitude and speed of population ageing since it entered the ageing society two decades ago. The rapid population ageing- driven by decreasing fertility rate and prolonged life expectancy- has profound impacts on economic development and poses significant challenges for formal and informal care provision. Although the Chinese government has implemented a series of progressive policy reforms on pension, healthcare, and long-term care systems, the capacity gaps regarding the coverage, (...) adequacy, affordability, and sustainability remain large. At the same time, social and economic changes have eroded the supportive role of family, especially for rural-dwelling, childless, and empty-nest older adults. This chapter documents the statistical and social reality of ageing in China, introduces a series of policy reforms implemented by the Chinese government in response to population ageing, and describes the family dynamics and intergenerational support patterns under the changing socioeconomic background. Besides pressing challenges of ageing for family and society, this chapter also looks at the emerging lifestyle and proactivity for active ageing in China. (shrink)

This paper proposes an index of national levels of “intergenerational solidarity”, defined as “investments or sacrifices that are intended to increase or sustain the wellbeing of future generations”. This is measured by examining changes to the value and stability of various capital flows and stocks. Nine indicators are drawn from national-level statistics: forest degradation rate, share of low-carbon energy consumption, and carbon footprint in the environmental dimension; adjusted net savings, current account balance, and wealth in equality in the economic (...) dimension; and primary pupil-teacher ratio, fertility rate, and GDP-adjusted child mortality in the social dimension. This returns a comparative index score of intergenerational solidarity for 120 countries covering 92% of the world’s population. Throughout, the state of the current research on intergenerational transfers and on the individual metrics used is discussed, and suggestions are made for further improvements and work in measuring intergenerational solidarity. As it stands, the index provides the widest coverage of indicators and nations aimed at measuring any similar concept. As such, it is particularly useful for those who wish to investigate the causes of intergenerational solidarity through cross-cultural comparisons. Online Appendix. (shrink)