User blog comment:Breakingmikey/A blog about stuff./@comment-1441098-20120330013030/@comment-1874924-20120330030222

There's a rule of thumb for determining what age difference in a romantic relationship is socially acceptable. It's obviously not a hard and fast rule, but the formula is to divide the older partner's age by 2, then add 7 to get the minimum age for the younger partner.

Obviously, there are exceptions. Most notably, "trophy" wives are often much younger than their husbands. I once heard about a 68-year-old man who had a 4-year-old half-brother. Usually, the way you get extreme age differences among half-siblings is for a man to outlive his first wife and then remarry to someone much younger.