Op-Ed

Nicholas Kristof

Earlier this year in Gujarat, India, I came across a most unusual kind of outsourcing: womb-rental.

Americans looking for a surrogate mother to bear a child can save a fortune and avoid regulations by paying an Indian woman $4,000 or $5,000 to carry their fetus. An embryo that has been created in vitro by the American parents is implanted in the Indian woman's uterus and she goes through the pregnancy and delivers the baby - and then hands it over to the Americans.

Ultimately, that kind of surrogacy could be mixed with genetic screening of embryos - to weed out babies of the "wrong" gender or with the "wrong" characteristics - to save busy couples the bother of pregnancy or the nuisance of chance.

Yes, all this gives me the willies, too. So some of the most monumental decisions we will face in the coming years will involve where we draw the line making some genetic tinkering legal and some illegal.

One of the crucial evolving technologies is P.G.D., or preimplantation genetic diagnosis. This allows a couple to test embryos...