It's certainly not just graying celebrities like Depp who rob the cradle. Research on the preferences of users of OK Cupid, one of America's most popular dating sites, indicates that "men show a decided preference for younger women, especially as the men get older... so, even though men and women are more-or-less proportionately represented on the site, men's decided preference for younger women makes for many fewer potential dates for women."

The culturally prescribed response to stories like Depp's or that of the OK Cupid data is a knowing nod: Older men chasing young women is a tale as old as time. According to that tale, heterosexual men who have the sexual or financial cachet to do so almost invariably leave the partners who aren't young enough to be their daughters for the women who are. In the popular imagination, men do this because they can—and because they're presumably answering the call of evolutionary and biological imperatives that push them irresistibly towards younger women.

By contrast, the contemporary hype about cougars and pumas revolves around smaller age-disparities. (A recent CNN story focused on the supposedly outrageous novelty of women in their 20s and 30s dating men an average of three years younger than themselves.) When it comes to inter-generational romances with age gaps sufficiently large that one partner could be the biological parent of the other, the course of true love remains maddeningly unidirectional.

What seems harmless and natural, however, is neither. A culture in which older men value younger women more than their own female peers does damage to everyone.

I'm not talking about the harm inflicted by pedophiles on pre-teen girls, which is both monstrous and a given. I'm not talking about the vile street harassment of adolescents by older men, which is also as toxic as it is infuriatingly ubiquitous. This is about the way in which young women come of age surrounded by reminders that they are at their most desirable when they are still at their most uncertain and insecure. Some young women are attracted to older men (for a host of possible reasons), but even these find too many men who are, in the end, deeply unsafe.

It's not just women who lose out as a consequence of this fixation on the older man, younger woman ideal. Ask women in their teens and 20s who are in relationships with older men about guys their own age, and you'll invariably hear laments about young men's immaturity. That callowness is often oversold by too many aging Lotharios wanting to emphasize the difference between their own supposed expertise and young men's clumsiness. The reality is that just as many young women "grow up too quickly" as a result of older men's attention, many young men grow up too slowly because of a lack of it. If men over 40 spent half as much time mentoring guys under 30 as they do chasing women in that age bracket, more young men might prove excellent partners to their female peers.