A few years ago, there was an article in Slate - Why Men Pay to Stay Married - which I found interesting. Seems that men's net income goes up when their marriages end and women's go down, with the opposite when they get married. Yet men marry again sooner than women do. Although he also assumes that this shows men are looking for Ms. Right but women are willing to settle for Mr. Right Now because of that ol' biological clock.

I think that applies only to a certain class of women - those who are willing to put off marriage/family until they feel they can't wait any longer, as opposed to women who get married in their twenties and therefore start looking earlier. Too many caveats in this article, maybe.