Global fertility decline is ringing demographic, economic, and social alarm bells. In a recent New York Times opinion piece, author Jessica Grose asks, “Are Men the Overlooked Reason for the Fertility Decline?” She provides compelling evidence to suggest that this phenomenon is not just about women delaying childbearing. Men, too, are contributing to declining fertility rates.

Indeed, in the United States, nearly one-quarter of men in their forties are childless, with more than one-third reporting that they would have wanted to have children. Even in Scandinavia, a region esteemed for its gender equality, rates of male childlessness are high. One-quarter of Norwegian men have no registered children by the age of 45, while in Finland, one-third of middle-aged men remain childless.

Some of the reproductive decline is due to male infertility, a serious and involuntary health problem that receives too little attention. Choice also plays a role, as men focus on other life goals, or make the decision to remain child free. However, an increasing percentage of declining fertility is unintended, as men in the U.S. and many other countries struggle to achieve the milestones of adulthood. Chief among these are higher education, stable employment, romantic attachment, marriage, and ultimately parenthood. Significantly, at current rates of male educational decline, there will soon be only one college-educated male for every two female college graduates in the U.S., or a ratio of 2:1. This “massive undersupply” of college-educated American men is what Jon Birger, in his prescient book Date-onomics, calls a “demographic time bomb,” especially for college-educated women who put a “high priority on getting married and having children in wedlock.”

In my new book, Motherhood on IceI spell out the reproductive consequences of this dearth of college-educated men for American women. The educational disparity between men and women is leading to what I call a “mating gap” — the lack of eligible, educated, equal partners for American women who hope to become mothers. These circumstances are leading many women to go without children, to become single mothers, to settle into unhealthy relationships, or, increasingly, to turn to technology.  American women are now freezing their eggs in record numbers. The lack of suitable men is the overlooked reason.

I learned this through interviews with more than 100 educated American women from diverse racial, religious, and regional backgrounds. Contrary to popular belief, women who freeze their eggs are not selfish careerists, immature partiers afraid of commitment, or gullible dupes of the fertility industry. Most were clear that they were not freezing their eggs for career planning purposes, or to climb the corporate ladder through company-sponsored egg freezing incentives. Rather, egg freezing occurred at an average age of 36, among women already well established in their careers. Yet, despite their professional success, 82% of these women were still single, with difficulties in securing a stable romantic relationship stated as their primary reason for egg freezing.

At age 37, Clarissa, an international economist, was representative in this regard. Never married and with no partner in sight, Clarissa felt mystified by her inability to find a suitable mate. “My career has been a sort of very happy part of my life. So, no problem with that,” she told me. But “the fact that it’s been hard to get into a relationship is the eternal mystery to me. And you try to suss [it] out, sort of like, “Is it me? Is it where I live? Is it because I have a career?”

Clarissa and many others like her noted that men often seemed intimidated by women’s career successes, especially men with less education and professional credentials. Kayla, an engineer in a Silicon Valley, put it this way, “You’re already under stress that you’re a highly accomplished female. That threatens a lot of men, unintentionally. And I’m not a threatening personality. But I certainly probably made more money than most of my guy friends, and I think the curse of smart women is you want to marry smart men, versus men who sometimes do the opposite. So, I think it does make it twice as hard for women who are accomplished.”

Nearly one-third of women I interviewed had been partnered in the past, but they were now divorced or decoupled from boyfriends and fiancés, leaving them single and concerned about their declining fertility. For example, Lily, an art curator, froze her eggs at age 40 after ending a 10-year relationship with a man she loved. “You know, he’s like one of the smartest people I’ve met, and funny, and so grounded,” Lily exclaimed, but then added, “And you know, totally flaky, and deeply indecisive, from a pathological standpoint… he just couldn’t commit. And I wanted to get married and have a kid, and he just couldn’t get there in the same timeline.”

Among the 18% of women I interviewed who were partnered, half had frozen their eggs because their relationships were unstable, while the other half were with men who were still “unready” to become fathers. Men’s unwillingness to commit to marriage and parenting was a recurring theme of women’s egg freezing stories. Women reflected on the “Peter Pans” who never grow up, the “beta males” drifting through life, and many other types of men unable or unwilling to form sustainable reproductive relationships with them.

Women like Clarissa, Kayla, and Lily all had the financial means to freeze their eggs. With a single cycle of egg freezing ranging from $10,000 to $20,000, cost is the procedure’s main limiting factor, leading to  the race- and class-based under-participation of certain groups of women. Furthermore, many women in my study felt discriminated against as single women. In the US healthcare system, being married and infertile can confer certain forms of health insurance benefits. But egg freezing cycles are rarely covered by health insurance, even though most single women are desperately trying to prevent their own future infertility. Educated women’s singleness is a societal issue, not their own fault. But they are being penalized through insurance policies that are simply unfair.

Clearly, the exorbitant costs of egg freezing need to be brought down. In addition, discriminatory insurance policies and inequitable state insurance mandates need to be revised to eliminate the bias toward married women. In this regard, access to egg freezing is an important reproductive justice issue among single women, both straight and gay, White and non-White, who are holding onto their dreams of becoming pregnant and bearing children. Although egg freezing is not a straightforward reproductive panacea, the barriers to egg freezing access are furthering disparities based on gender, race, class, age, sexual orientation, and marital status, all off which end up privileging reproduction for some women at the expense of others.

Until we “fix men,” as one of the women in my study put it, egg freezing will remain educated thirty-something women’s single best reproductive option—a techno-medical solution to a fundamental gender inequality that provides them with some hope and allows them to retain their motherhood dreams. Only by listening carefully to what educated women have to say can we begin to understand the magnitude of their “men as partners” problem, and why it is has become the leading but overlooked cause of egg freezing in the U.S. and beyond. Rather than being an expression of selfish desires or immaturity, it is for many women the only viable solution to a societal problem that is beyond their control.