A defense of "May-December" marriages like Hugh Hefner's.

But every relationship has power imbalances, whether in terms of income, intelligence, or social status. The age gap is different only in that it may be more visible. It therefore gets blamed when a marriage goes bad. "A couple with an age disparity can stop right there and say they're not getting along anymore because the older person's gotten too old or too sick," when in reality they might just have a communication problem, says Gayle Luster, a marriage counselor who is herself the May to her husband's December. (Maybe more like August to October—she's 53 and he's 68.) When a couple gets divorced, other people are likely to blame the age gap, too.

There's also a squirm factor in age gaps. Hefner likes oversharing about his Viagra-fueled libido, as do his many girlfriends. Woody Allen and Morgan Freeman struck up relationships with the daughters (and in Freeman's case, the granddaughter) of former wives or lovers. And of course no one likes to think about Fred Thompson's unclothed body. As the priest in Harold & Maude puts it: "I would be remiss in my duty if I did not tell you that the idea of intercourse—your firm, young body, comingling with withered flesh, sagging breasts, flabby buttocks—makes me want to vomit."

Gap haters ignore the benefits of age disparity. Older people tend to have more stability in their lives—financially and emotionally—that could appeal to a young person adrift in his 20s. Likewise, an older person may benefit from proximity to youth. Sure, one person could fall into a parental role while the other is infantilized. But that's a risk in any relationship.

But the best reason not to hate May-December marriages is the same reason not to hate any marriage that's not your own: What's the point? In the case of marriages like Hugh Hefner's, you're arguing against an ancient biological imperative for men to marry women of child-bearing age, and the need for material security in which to raise those children. Likewise, there will always be young men who don't want or already have children and who are attracted to older women. And anyway, even if it is a mistake, one partner is likely to expire before the marriage does.

Click here  for a slide show of celebrity May-December romances.

Correction, Dec. 29, 2010: This article originally misspelled Crystal Harris' first name. (Return to the corrected sentence.) Correction, Dec. 30, 2010: This article originally misidentified the film To Have and Have Not as To Have and To Have Not. ( Return to the corrected sentence.) Correction, Jan. 5, 2011: This article originally misspelled Charlie Chaplin's last name. (Return to the corrected sentence.)