Due to their effect on maternal testosterone levels, sons are said to have reduced maternal longevity in pre-industrial humans. This analysis, using information from a Flemish agricultural village in the 18th-20th centuries, confirms the presence of a negative effect of sons on maternal longevity. However, the effect is mainly observed for mothers belonging to the least privileged social group and for sons surviving their fifth birthday. Both findings make the above-mentioned biological explanation relative. However, a plausible alternative, social interpretation is male-dominated intra-household resource competition. It is reasonable to assume that only sons above a certain age are able to claim a serious amount of resources and that competition is strongest within the least privileged social group.