The Young Women of the Sea? USU graduate investigates old Naval belief

By Christopher Austin

There’s a long held belief in the Navy that Sailors who serve on submarines are more likely to have daughters than sons compared to non-submariners. One Uniformed Services University of the Health Sciences (USU) graduate is putting that wives’ tale to the test.

“I’d been hearing in the community for a number of years that submariners tend to have more girls than the rest of the population,” said Navy Lt. (Dr.) Kathleen Kramer. “I heard that and wondered if that was true, and if so why. I thought I would take a stab at figuring out if it’s true.”

For her USU senior capstone project, Kramer, who graduated in 2017, decided to conduct a survey of thousands of submariners in the Navy with the goal of determining if there is significant evidence that those who serve on submarines are more likely to have girls than those who do not.

“There have been two prior studies of sex ratio in offspring of submariners, one by Bachmann in 1970 and again by Volk in 2004. Bachmann found a higher ratio of female offspring in personnel serving aboard US Navy nuclear submarines than the general population. Volk concluded that this belief is probably not true; however, he did find a higher chance of female offspring correlated with a longer time in the community, as well as an increased ratio in sonar technicians,” Kramer said.

These studies were on a small scale, though, and did not differentiate between submariners who were stationed on subs and those who were serving on shore duty, or where on the sub they were assigned. Kramer’s study seeks to clarify this in a survey she developed alongside Army Lt. Col. (Dr.) Kimberly Hickey (USU ‘99) assistant professor in the Office of Graduate Medical Education, and one of her mentors on the project, and Dr. Cara Olsen (USU MPH ‘04 and DrPH ‘08) from USU’s Department of Preventive Medicine and Biostatistics (PMB).

When on sea duty, submariners are stationed on submarines like the USS Kentucky. Kramer’s study aims to determine if there is evidence to suggest that the long-held belief that those who serve on submarines are more likely to have daughters than sons is true. (Image Credit: United States Navy)

“Her approach is to try to contact everyone in the Navy who has been on submarine duty – officers and enlisted – then try to survey them as to all their living children and when the children were born,” said Dr. Martin Ottolini, assistant dean for Capstone Projects, another of Kramer’s mentors on the project. “Were they associated with an assignment to an actual boat at sea? Or was it when you were assigned to shore duty?”

While there is no certain origin to the belief at the core of Kramer’s study, it is generally believed to have started in the 1970s with the introduction of nuclear submarines. Some have theorized it might stem from apprehension towards nuclear power that the era brought about, but that is only one of the unique environmental variables that submariners are exposed to when on board a submarine, any of which could have some unknown impact on the sex of unborn children. But that’s a study for another time.

“The first step is to see if there is a difference in the sex ratio. Once that question is answered, then I think it would be interesting to look into why that is,” said Kramer. “Of course, it would be a very different question because there are so many variables. Lots of people have studied sex ratios in different communities with different environmental exposures and occupations. All those research articles have a hard time saying what exactly the mechanism is for altered sex ratios. There’s a lot of theoretical articles that I’ve read about hormone levels and things like that, but it’s all theory.”

Kramer and her mentors don’t know what the outcome of the survey will show, but are confident that the Naval community will be interested at the very least, giving families a degree of insight into how they might want to plan their deployments. She has a personal investment after all: her husband is a submariner and they recently had a baby daughter.

“I hope it’s something interesting to the submarine community… Through the approval process, I had to get approval from the commander of the submarine forces,” she said. “They asked me, in return for their approval, that I share the information with them. Hopefully they will find it interesting as well.”

Kramer's research poster entitled "Sex Ratio in Offspring of U.S. Submarines"