Baby, It's You! and You, and You...

Before we assume that the market for human clones consists mainly of narcissists who think the world deserves more of them or neo-Nazis who dream of cloning Hitler or crackpots and mavericks and mischief makers of all kinds, it is worth taking a tour of the marketplace. We might just meet ourselves there.

Imagine for a moment that your daughter needs a bone-marrow transplant and no one can provide a match; that your wife's early menopause has made her infertile; or that your five-year-old has drowned in a lake and your grief has made it impossible to get...