The sky-high cost of having a first child can also include leaving your STEM job.

About four in 10 women (43%) leave their full-time employment in science, technology, engineering and mathematics following the birth or adoption of their first child, according to research recently published in the peer-reviewed Proceedings of the National Academy of Sciences. Men aren’t immune, either: 23% of new dads do the same.

New parents, the researchers write, “are significantly less likely than similar childless respondents to remain in STEM full time” — both right after having their first kid, and as that kid hits school age.

“ Over 10% of female STEM professionals go on to work part-time STEM jobs after having their first kid, while around 15% exit the workforce entirely. ”

Co-authors Erin Cech, an assistant professor at the University of Michigan, Ann Arbor and Mary Blair-Loy, a professor at the University of California, San Diego, used nationally representative National Science Foundation data collected from 2003 to 2010.

Just over 10% of female STEM professionals go on to work part-time STEM jobs after having their first kid, while around 15% exit the workforce entirely. That’s compared to just 2% of new dads who go part-time in STEM, and 3% who leave the workforce. What’s more, many of these STEM defectors — 18% of new fathers and 12% of new mothers — go on to work full-time jobs in non-STEM fields after becoming parents.

The findings suggest that “parenthood is an important driver of gender imbalance in STEM employment,” wrote Cech and Blair-Loy. For example, women make up just 21% of computer programmers, 16% of folks working in architecture and engineering, and 26% of those in computer and mathematical occupations, according to the Bureau of Labor Statistics.

But it’s not just a woman problem, they added. “The difficulty that these professionals may face in balancing caregiving responsibilities with full-time STEM employment suggests that this issue is a concern for the STEM workforce broadly and not just for the retention of women,” they wrote. “Thus, scholarly and policy literature framing child-rearing responsibilities as solely a women’s problem is short-sighted.”

“ ‘This issue is a concern for the STEM workforce broadly. Scholarly and policy literature framing child-rearing responsibilities as solely a women’s problem is short-sighted.’ ”

Cech and Blair-Loy do offer some avenues for improvement. They point out there’s a need for paid parental leave on the legislative front, as only California, New Jersey, New York, Rhode Island, Washington and the District of Columbia offer paid family-leave programs, and the federal government offers none.

Organizations can also institute better parental leave and flexibility policies, they added: Only 15% of private industry, state and local government workers enjoy paid family leave — and while the Family Medical Leave Act (FMLA) allows eligible workers to take up to 12 weeks off, employers aren’t required to pay them.

The study co-authors further highlighted “the need for STEM leaders and employers to confront cultural beliefs that STEM professionals with caregiving responsibilities are less valuable and less committed to their professional work” than child-free colleagues.

“These findings point to the importance of cultural shifts within STEM to value the contributions of STEM professionals with children and the need for creative organizational solutions to help these skilled STEM professionals navigate new caregiving responsibilities alongside their STEM work,” Cech said in a statement.