Parental investment theory postulates that where physical condition varies significantly then birth sex ratio will be correlated with social status. Application of this theory to man remains contentious. This study examines physique, wealth, and social status in relation to the sex of live births. It reports a female-biased sex ratio in high social and economic status Nepalese. Close consanguineous marriage, intended to conserve landed wealth within related lineages, and increased female work burdens accompanying larger farm size, are proximate factors which may underlie this finding. A differential payback hypothesis is one way of explaining this pattern.