Say the word “market,” and what comes to mind? Financial markets, maybe, or supermarkets. There are markets in real estate, markets in used cars, markets filled with farmers selling green beans and cheese. But a market in human fertility—sperm, eggs, hormones, surrogate mothers, embryos? Babies, or the means to make them, aren’t supposed to be sold. They aren’t supposed to be bought. They aren’t supposed to have prices fixed upon them.

A version of this article appeared in the February 2006 issue of Harvard Business Review.