Truth Theorem

A friend read that in 70 percent of relationships, men will cheat, but I've seen all sorts of different stats. Do you have reliable numbers on the level of cheating that goes on?

--Tabulating

You can get pretty reliable stats on cheating, providing you restrict your inquiry to two-timers with wings and a beak. Researchers who test baby bird DNA find that up to 60 percent of the chickies weren't fathered by the mommy birdie's partner. (And, P.S. Don't believe the clever public relations campaign of those sluts, the swans.) In humans, data is "self-reported," as in, "Here's a number two pencil: Tell the truth about your sex life." The results are highly accurate -- if you don't count everybody fudging to seem more studly or less hussyish and cases where everything but "and" and "the" is a lie. The bottom line? Men cheat, women cheat, and if you've ever been involved with a man or woman, there's a good chance you've been cheated on. Delve into your partner's character and views on monogamy before you commit, and you might avoid hiring a private detective or DNA lab to do it afterward -- when you can't help but notice that your wife's a vulture who just gave birth to the most beautiful baby duck.