Now that most women are glumly grappling with the widespread medical consensus that, if you want to have a baby, you’d best do it by age 35, here comes more exciting news from the research community: Firstborn children to mothers under 25 are nearly twice as likely to live to be 100 than those born to mothers over 25. In terms of public relations, the ad lines write themselves: Give your baby the gift of a century, have him when you’re barely done with college. As a bonus, teenage moms finally might catch a break.

In fairness, the research by the University of Chicago’s Center for Aging did not set out to make older mothers feel guilty about the potential lifespan of their children. Study authors Leonid A. Gavrilov and Natalia Gavrilova were trying to determine why firstborn children were more likely to reach their 100th birthdays than those born later. Using census and Social Security Administration data of 198 “validated centenarians” (it seems there are a lot of fakers out there), they found that the mother’s age played a surprisingly important role.

“What is really interesting is that the survival benefits of being born to a young mother are observed only when the mother is younger than 25 years,” Gavrilova reported at a recent meeting of the Gerontological Society of America. “This may have important social and actuarial implications, because so many women now decide to postpone childbearing due to career demands.”

Here we go again. Not only do we risk infertility and birth defects if we try to have a kid past 35, now we can feel bad about our children dying “young” because we spent our early 20s not procreating but monkeying around in graduate school or trying to rise out of entry-level jobs.

So in case you missed the memo the first 400 times: Tick tock, ladies!

Will women never escape being told what is the proper age to make major life decisions? Even though nearly 40 years have passed since feminism entered the national consciousness, we’re still governing much of our lives based not on what’s best for us but on whether there is a culturally sanctioned, scientifically proven window of opportunity to do what we think we’re supposed to do. The result is that the game of femaleness, like the game of football or basketball, is ruled by the clock.

And I’m not just talking about the biological clock. Long before most women have an ounce of concern about the viability of their eggs, they’ve been well informed of the pitfalls of not planning. Delay college too long, we’re told, and you’ll wind up answering phones about the time you should be getting your own office. Settle down before you’re 28 and you’ll have cheated yourself of the all-important “experimental phase,” (promiscuity? a switch in sexual orientation? dating a drummer?) which, in certain circles, is considered a prerequisite to finding someone reasonable. Put off permanent commitment until your mid-30s, however, and you’re dealing with a very limited pool of potential mates.

As for the baby question, we all know the drill. Start a family in your 20s and you’ll likely face serious economic obstacles that might even bar you from the middle class. Wait around much longer and, well, we all know how that story turns out.

What we’re left with is a female life plan that is so beholden to tight schedules that even with careful timing you can’t win – you’re either fighting biology or you’re embarrassingly retrograde and unambitious.

Maybe they’ve managed to buck my generation’s biases against marrying young and just committed themselves to someone they loved. Or maybe the fertility alarmism of the past decade has created a new kind of tyranny, one that’s not so easily dismissed as a trapping of bourgeois angst.

In any case, I hope the University of Chicago study doesn’t get much more play than I’ve given it here. Mothers of any age have enough guilt without worrying about their children becoming centenarians. Besides, the only thing worse than having kids before you’re ready is knowing that they could be talking about you in therapy until they’re 100.