Fertility and infant survival in men and women from rural regions of Northern Tanzania: gene candidates and sex-specific genetic associations.

Numerous factors, including family planning and modern contraception, disturb the potential associations between the number of children born and genetic factors in modern Western societies. The current progress of medicine and a relatively high level of well-being make it hard to test the association between children's survival rates and genetic factors in Western societies either. The goal of the current study was to reveal the possible associations between the number of children born and the number of children survived till the age of 5 y. by the time of our study with a set of six genetic polymorphisms associated with serotonin, dopamine, androgen oxytocin behavioral effects; and to test for sex-specific effects of these polymorphisms in a traditional rural sample from Arusha and Singida Districts of Northern Tanzania. The data on 965 healthy individuals (520 men and 415 women) from traditional rural communities with high reproduction profiles were collected. All participants provided information on the number of children born and survived, and other demographic information, as well as buccal epithelium samples for DNA analysis. The data were analyzed using GLM ANCOVA and the APSampler nonparametric methodology. The gene association effects on reproduction and infant survival in men and women were demonstrated. We suggest that sex differences revealed in this study are in line with sexual selection pressure on reproduction and parenting in traditional societies.