It saddens me to know couples in their late thirties trying unsuccessfully to conceive. The notion that it is easy to conceive at any age under 40 — and perhaps beyond that — has taken firm, but mistaken, hold in our culture. The American College of Obstetrics and Gynecology recently published a meta-analysis concluding that women’s fertility begins to drop significantly at age 32 and drops rapidly at 37. This study reaffirms a similar 2008 statement by the American Society for Reproductive ­Medicine.

Most people have not heard of these studies. Many who know the general concept discount it. The broad postponement of parenthood rests on a series of dubious cultural notions.

Initially, the belief that one has at least until age 40 to conceive probably gained currency because 40 is a round number. It provides a defined amount of prospective liberty to sample the companion field, develop one’s career, travel, and pursue other personal interests. But the body is calibrated to nature, not to round numbers or the fulfillment of bucket lists. Many of us procrastinate in many aspects of our lives. Americans often manage conception as they do money or weight: they focus on the present and leave little margin for the future.

Americans have widely internalized the notion that, despite many millennia of human history, biology has recently changed, and they are suddenly aging better than their parents; fifty is the new forty, and so on. Our parents’ generation may have smoked more, eaten less well, gone to the gym less often, dyed their hair less, dressed less fashionably, and listened to less hip music through their thirties than do their modern counterparts. But looking slightly younger, having Jay-Z on your iPod, or being able to run 5Ks does not reset the biological clock or enhance reproductive function.

Furthermore, most Americans are exceptionalists; we think that rules about risk and failure that apply to others don’t apply to us. Our books and movies foster the belief that the individual is the master of his own destiny, and that the force of will can surmount any challenge. Those who have heard of the biological clock think they will have exceptional reproductive longevity. Or they think the exception can become the rule: because their 41-year-old neighbor — who had her first child years before — is pregnant, a first-time pregnancy is virtually guaranteed for them at 38.

Dubious Notions

Our culture has also developed the dubious notion that it is never too late to try anything. From the 80-year-old skydiver on down, the “Man Bites Dog” media feeds the notion that any age-based limits on conduct are intrinsically suspect. Mothers or grandmothers who hint at a fertility end date are dismissed as archaic and insensitive. But science bears out their concerns. If a food additive had a fraction of the effect on fertility that age does, every form of protest would be marshaled against it.

Our culture also encourages us to believe we can all have it all. Many people postpone childbearing in order to obtain an advanced degree, (especially in our formal education-intensive culture), build a career, and save money. But doing so projects adults’ material desires onto kids, who are as happy playing with a kitchen pan as with a store-bought toy and care little about the kind of dwelling they inhabit. Perhaps some moneymaking can wait. Maybe we can have it all, just not all at one time. Or maybe we simply can’t have it all.

Perhaps most fundamentally, the willingness to postpone conception until one’s late thirties is based on the culturally encouraged but mistaken notion that women and men are equal in all ways, including biologically. Laws and cultural messages can foster notions of gender equality, but biology does not conform to these notions.

Though it seems paradoxical to say it — perhaps because they were so widely touted as boons to women — synthetic birth control and abortion have placed women at a great disadvantage relative to men. As both Pope Paul VI prophesied in 1966 and current Fed Chair/then college professor Janet Yellen chronicled in 1992, these technologies have given men full, consequence-free (save for STIs) access to multiple women’s bodies for decades. As long as women remain sexually available, a man can outwait the woman looking critically for Mr. Right and cause her to accept Mr. Right Now when she’s in her late thirties. Men can wait considerably longer before having to settle for Mrs. Right Now. It’s not fair, but this scenario plays out frequently.

Ramping Up the Process

When fertility is lost to time, many Americans turn — as they do in other realms — to technology and public subsidies. But IVF is fraught with significant, glossed-over problems, from the pain and risk of the treatments themselves to the complicated pregnancies, embryo surpluses — both in utero and in laboratory freezers — eugenic embryo selection, post-implantation selective reduction (i.e., abortion), and increased risk of birth defects. There are also great material costs with respect to both personal finances and societal medical and insurance resources.

And IVF often fails for those over 35. By that age, a woman’s eggs have decreased in both number and quality. Thus, the process is ramped up: if a woman had her eggs harvested and frozen, she uses those; if not, she uses eggs harvested from well-pedigreed college students, who risk their own health and future fertility to enable older women to do what our society once considered indecent: allow their husbands to have the child of another woman.

Moreover, like many commercial processes, surrogacy allows childbearing to be outsourced to low-income women in the U.S. and abroad. That exposes many poor women to exploitation and abuse.

For all these reasons, postponing parenthood is a high-stakes risk. Americans should examine the cultural notions and technologies that facilitate this dysfunctional trend.