Evaluating the sex ratio in the offspring of U.S. Navy submariners

In 1970, a study completed in accordance with the Naval Submarine Medical Research Laboratory in Groton, Connecticut, concluded that U.S. Navy personnel serving aboard nuclear-powered submarines tended to have a higher ratio of female offspring compared with the general U.S. population. To date, there has not been an examination as to whether or not this remains true today.

Estimation of the sex ratio (SR) in the offspring of the current U.S. Navy submariner population, examining potential contributing factors, including rating, rank, and tobacco use, was the aim of this study.

Between November 2002 and May 2003, 597 male active duty U.S. Navy submariners were surveyed in reference to their age, rating, and rank, time in the submarine community, age and gender of their children, and their lifetime tobacco use.

Of the 597 submariners who completed the survey, 259 of them had fathered children. A total of 413 submariner offspring were included in the results. Of these offspring, there were 222 boys and 191 girls, forming a SR (percentage of male offspring) of 53.75%. Unlike the study from more than 30 years ago, there was no statistically significant difference compared with the SR of the U.S. general population during this time, 51.17% (p = 0.29). However, within the study population, there was a trend toward lower SRs as the father's total time in the submarine community increased (p = 0.06). A stratified analysis by rating found that sonar technicians had a statistically significant lower SR of 34.5% (p = 0.03). Smokers were noted to have a higher ratio of male offspring compared with non-smokers, although this finding was not statistically significant (p = 0.46).