It's not about career planning. As a medical anthropologist, I can tell you that women are freezing their eggs because of partnership problems.

• The following is an adapted excerpt from the book "Motherhood on Ice: The Mating Gap and Why Women Freeze Their Eggs."
• Marcia C. Inhorn, the author, is a professor of anthropology and international affairs at Yale.

The following is an adapted excerpt from Marcia C. Inhorn's book "Motherhood on Ice: The Mating Gap and Why Women Freeze Their Eggs," forthcoming from New York University Press (May 2023).

As a medical anthropologist and gender scholar, I have been privileged to gather egg freezing stories from 150 American women across the country. As my study clearly reveals, these women are part of a particular US demographic of highly educated professional women who are now turning to egg freezing by the thousands.

Eighty-two percent of all the women in the study were single, with no partner in sight. All but three of these single women were heterosexual, and even the three bisexual women declared an interest in partnering and parenting with men. Yet the lack of a partner was a shared feature of women's lives, as it has been in every single egg freezing study ever conducted.

Relationship problems are causing egg freezing

Single women in this study were of two types: the never married and currently unpartnered, and the previously partnered but broken up. Half of all women fell into the first category. Some of these women had had one or more serious relationships in the distant past, but those relationships had ended some time ago. Some women had never been in a serious relationship for reasons they could not quite understand. Many of these single women expressed regret and puzzlement over how they had "ended up" this way. But without a partner, these single women had turned to egg freezing to "buy time" while continuing to search for a partner with the hope of future marriage and motherhood.

The second group of single women, nearly one-third of the total, were turning to egg freezing in the aftermath of relationship break-ups. These included both divorces and breakups from long-term relationships and engagements. Although these women's stories will be told in greater detail, suffice it to say here that these relationship traumas were often painful, leaving women quite bereft. In such cases, egg freezing provided a path to healing, as women attempted to repair their disrupted life courses.

Between the never-married singles and the women whose relationships had ended, four-fifths of women in this study were single. Being single — or what other studies describe as "lack of a partner"— was the main reason these women had frozen their eggs.

But even women with partners faced ongoing partnership problems. In this study, about one-fifth of the women had a partner at the time of egg freezing, but half of these relationships were unstable. Several women had met "new boyfriends" around the time of egg freezing. But in these cases, it was very difficult for them to ascertain whether the relationship was going to last. In other cases, women found themselves in very unstable relationships with partners who were immature, unsupportive, unready to have children, or unfaithful. In these cases, it was very unclear whether the relationships would survive. In both cases, egg freezing was being undertaken as a kind of backup plan, to see whether a relationship would develop or fall apart.

Among the nearly 10% of women who were in stable relationships, women were undertaking egg freezing while waiting for their partners to be "ready" to have children. Men who were "unready" cited various reasons for their delay, for example, completion of advanced degrees or professional training, significant career moves, or in some cases, because they were significantly younger than their female partners. In other cases, men simply did not feel prepared to become fathers and were asking their female partners to wait.

In summary, 91% of women in this study were either single or in a tenuous relationship — the relationship problems that underlie the egg freezing phenomenon. To wit, highly educated American professional women are often trying their hardest to find compatible male partners, with whom they can build families. But these stories exemplify women's three major partnership challenges:

• Men who are reluctant to partner with high-achieving women, leaving these women single for many years.
• Men who are unready for marriage and children, often leading to relationship demise.
• Men who exhibit bad behavior, including infidelity and ageism, which often leads to relationship instability and rupture.

Men as partners are the problem

Because of these heterosexual relationship problems, otherwise-accomplished American women are pursuing a stopgap measure — namely, egg freezing — in an effort to preserve a path to motherhood.

Although this may seem like an obvious point, reproduction is inherently relational. It requires both men and women, or at least their sperm and their eggs, to come together in procreation. Ideally, it also involves men's and women's emotional investments in one another and in their children. But what happens when these reproductive relations and investments are untethered and go missing? In international reproductive health circles, this issue has been called the "men as partners" problem: Men in the Global South have been heavily criticized, sometimes fairly, sometimes not, for their negative influences on women's reproductive lives and well-being, including the abandonment of their female partners and offspring.

I argue that educated American women have a specific "men as partners" problem as well, one that needs to be recognized, called out, and confronted. In the women's stories told in "Motherhood on Ice," the lack of stable reproductive relationships is the bane of women's existence, with significant deleterious consequences for women's reproductive lives.

Although this is a "First World professional women's problem," as one woman put it, it is nonetheless forcing them into a demoralizing state of reproductive suspension. Only by listening carefully to what educated American women have to say about this can we understand the magnitude of this American mating gap and why American women are turning to egg freezing as a reproductive suspension bridge.