Offspring sex ratio of male active duty U.S. Navy submariners, 2001-2015

The natural human sex ratio at birth (male:female) slightly favors males, and altered sex ratios might be indicative of exposure to reproductive hazards. In the U.S. Navy submarine community, there is a widespread belief that submariners are more likely to father females, but corroborating scientific evidence is limited. To assess this, Department of Defense Birth and Infant Health Research program data were used to identify 7,087 singleton infants whose fathers were considered submariners. Chi-square tests and unconditional logistic regression models were used to compare the offspring sex ratio of male submariners with 2 other active duty populations and the U.S. population. The offspring sex ratio of male submariners was 1.048, which did not substantially differ from the sex ratio of each comparison population. Furthermore, this study found no meaningful variation in offspring sex ratio by length of submarine or military service or by rating.