Consanguineous marriages are strongly preferred in much of West and South Asia. This paper examines the prevalence and sociodemographic correlates of consanguineous unions in Pakistan using local and national data. Information from 1011 ever-married women living in four multi-ethnic and multi-lingual squatter settlements of Karachi, the main commercial centre of the country, are compared with data from the national 1990/91 Pakistan Demographic and Health Survey (PDHS), based on information provided by 6611 women. Both sets of results indicate that approximately 60% (...) of marriages were consanguineous, over 80% of which were between first cousins. The mean coefficients of inbreeding (F) in the present generation were 0·0316 and 0·0331 for the Karachi and PDHS data respectively. In both surveys the prevalence of consanguineous unions appeared to be unchanged over the past three to four decades. Consanguineous unions were more common among women who were illiterate or had only primary level education, were first or second generation migrants from rural areas of Pakistan or, in the PDHS, lived in rural areas, and whose parents were also consanguineously married. (shrink)

The effects of religion, population sub-division and geography on the prevalence of deaf-mutism were investigated using information collected in the 1921 Census of Punjab. The total sample size was 9·36 million, and comprised data on thirteen Hindu castes, seventeen Muslim biraderis and two Sikh castes. A two-way analysis of variance comparing males in Hindu castes in which consanguineous marriage was prohibited, with males in Muslim biraderis which favoured first cousin marriage, indicated major differences with respect to the patterns of deaf-mutism (...) within each religion. In the Muslim population 9·1% of the relative variation in the prevalence of deaf-mutism was inter-biraderi, 36·8% between geographical regions, and 48·8% an interaction between biraderi and region, whereas among Hindus 46·8% of the observed variation was inter-caste, 12·8% inter-region and 33·6% due to caste–region interaction. From a wider disease perspective the results obtained with the Hindu community indicate the significant genetic differentiation associated with caste endogamy. As the overwhelming majority of Hindu marriages continue to be within-caste, it can be predicted that similar levels of inter-caste differences in disease frequency currently exist. By comparison, the lower level of inter-biraderi variation among Muslims is probably indicative of the dissolution of pre-existing caste boundaries and the resultant gene pool mixing that followed the large-scale conversion of Hindus to Islam during Muslim rule in North India from the 13th to the 19th centuries. (shrink)