Female genital cutting and mother's age at birth are associated with the sex of offspring in Africa.

Female genital cutting (FGC) is widespread in Africa. Its short and long term medical consequences are widely reported. Here we report that FGC is associated with and may contribute to increases in the sex ratio at birth (Odds Ratio = 1.019; 95% C.I. = 1.007, 1.032) while mother's age at birth is inversely associated with probability of male birth (Odds Ratio = 0.998; 95% C.I. = 0.997, 0.999) in a generalized linear, logistic model with the probability of a male birth the dependent variable and eight potential explanatory variables applied to 413,384 births in 22 African countries. While these two associations are statistically significant, their odds ratios are close to 1.0 and they only slightly decrease the null deviance of the model. Therefore sex determination in these data is still a mostly stochastic process determined by the random variation in X or Y sperm production, transport, and conception.