As Fortune‘s Leigh Gallagher reported at the time, critics derided the new benefit as “a self-serving move to encourage women to take their eye off the biological clock so that they could double down and work harder throughout their 30s. It was paternalistic, sexist, and a trick to keep women childless and living at the office, all wrapped in the cloak of concern over women’s fertility issues.”

But a new study of 150 women who had undertaken elective egg freezing at eight clinics in the United States and Israel found that more than 90% said they were not intentionally postponing their fertility because of education or careers. Rather, they were preserving their fertility because they were single without partners to marry. Women lamented the “missing men” in their lives, viewing egg freezing as a way to buy time while they continued to search for a committed partner.

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“In the media, there’s been this narrative that career women are putting off having children for the sake of their careers,” says Marcia Inhorn, the study’s lead author and a professor of anthropology and international affairs at Yale University. That’s incorrect, she says. “They want to be married or at least partnered [before having a child] and they haven’t been able to find anyone.” Inhorn’s unpublished study was presented at the European Society for Human Reproduction and Embryology conference in Geneva this week.

A round of egg freezing costs approximately $10,000, plus storage fees, and women often need at least two rounds to collect the necessary number of eggs.

Women in the study were highly educated, with more than 80% having earned at least a graduate degree. Their failure to find a partner, Inhorn surmises, points to the “lopsided college graduation rate,” in which more women are graduating from college and advanced degree programs than men.

A 2017 report from the National Center for Education Statistics found that since 2000, degree attainment rates among 25- to 29-year-olds have generally been higher for females than for males at each education level. The gender gap last year for students in that age range was about 8 percentage points for bachelor’s degrees or higher and 4 percentage points for a master’s or higher degree.

In the 2015 book Date-Onomics, which delves into the math behind finding a suitable mate, economics writer Jon Birger writes: “The college and post-college hookup culture, the decline in marriage rates among college-educated women, and the dearth of marriage-material men willing to commit, are all byproducts of lopsided gender ratios and a massive undersupply of college-educated men.”

One way to resolve this mismatch is to “get boys off to a better start” so more of them attain higher education, Inhorn says. But a more comprehensive solution may be to update gender roles and what’s expected of each sex across the board.