Women’s educational and professional achievements in recent decades have, in many ways, diminished the need for marriage.  Add to this, of course, the sexual revolution of the 1960s, major advancements in birth control, and loosening of divorce laws and marriage no longer holds the weight it once did.While marriage is clearly not obsolete, there are many instances in which men and women are putting off marriage. And with that postponement they are also putting off having children.

Twins, once a novel sighting, are no longer something to bat an eye at. And anyone with school-aged children – especially in urban communities – are well aware that parents are noticeably older than in previous generations.  But while I am familiar with parents in their 40s starting families, I was less aware of the phenomenon Lisa Miller describes as “Parents of a Certain Age” in the October issue of New York Magazine:

You know such people. They are your colleagues and friends, your boss or your mother’s cousin. You see them on the subway—as I did recently at the Bloomingdale’s stop. From behind, the woman looked like a Manhattan-mom archetype: a slim-hipped, pony-tailed blonde in jeans struggling with a stroller. As I passed her, I saw that she had the too-tanned and haggard face of a very fit grandma. In parks and playgrounds, you note a grizzled grown-up and his dimpled charge, and you do the math and you wonder.

The age of first motherhood is rising all over the West. In Italy, Germany, and Great Britain, it’s 30. In the U.S., it’s gone up to 25 from 21 since 1970, and in New York State, it’s even higher, at 27. But among the extremely middle-aged, births aren’t just inching up. They are booming. In 2008, the most recent year for which detailed data are available, about 8,000 babies were born to women 45 or older, more than double the number in 1997, according to the Centers for Disease Control. Five hundred and forty-one of these were born to women age 50 or older—a 375 percent increase. In adoption, the story is the same. Nearly a quarter of adopted children in the U.S. have parents more than 45 years older than they are.

The baby-having drive in this set is so strong it’s recessionproof. Since 2008, birthrates among women overall have declined 4 percent, as families put childbearing on hold while they ride out hard times. But among women over 40, birthrates have increased. Among women ages 45 to 49, they’ve risen 17 percent.

Reproductive technology accounts for the sharp rise in the numbers. Women over 45 who want to carry their own babies most often use donor eggs, though egg freezing, a more cutting-edge method, offers early adopters another option, a kind of reproductive DVR for circumventing the inflexible and often inconvenient schedules handed down by Mother Nature. (Save your shows, and watch them when you have time; put your own eggs on ice, and wait for Mr. Right.) Egg freezing now gets write-ups not just in medical journals but also in Vogue, where a long feature on the technology appeared this past May between articles on avant-garde gastronomy and the fashionable art of mismatching patterns.

But just as important as those medical advances is a baby-crazed, youth-crazed culture that encourages 50-year-olds to envision themselves changing diapers when a decade ago they might have been content to calculate the future returns on their 401(k)s. Nothing—not a sports car, not a genius dye job—says “I’m young” like a baby on your hip.

I have to say after reading the article, letting it marinate for a few days, and considering all the various angles Miller presents, it’s clearly not a black-and-white issue.  I applaud women’s accomplishments and recognize the challenges that come with trying to build a career and have a family.  (It’s certainly a balancing act I’m very familiar with.) Nor do I believe one kind of family is necessarily better than another. It’s true younger couples may have the energy desired for raising a family, but an older couple is apt to have more experience, more knowledge and perhaps better judgment.

Still it’s hard to wonder if the modern feminist movement born of the 1960s, which so greatly devalued the importance of marriage, and which continues to view marriage as inherently inequitable, isn’t at least in part responsible for this new parenting trend.