In a few years, you can bet on it. Baby Girl Who is going to turn to her parents and ask, "Where did I come from?" This question won't bring on the normal, scaled-down, blushing nursery lecture about sex. Oh, what a different tale these parents have to tell.

Baby Girl Who (as in "Who" does this baby belong to?) was conceived last August. The egg and sperm of a couple from New York got together in a petri dish in Cleveland. What came from this union was an embryo. The embryo was implanted into the womb of a woman from Detroit.

The genes of the first woman and her husband were nourished and carried in the uterus of the second woman who was paid $10,000 for fetus care. Then, on April 13, in Ann Arbor, Baby Who was delivered into the arms of the couple from New York.

This is a story complex enough to make the average parent long for the simple delivery system of the stork. In the origin of this member of the species, the birds and the bees had less to do with reproduction than doctors and lawyers. For the very first time, the word "mother" was not defined in the delivery room, but in the courtroom.

Baby Who was the product of one woman's genes and another woman's womb. She had, in effect, a genetic mother and a gestational mother. These two women were not in conflict; indeed, they were in cahoots. The genetic mother was fertile but had no uterus. The gestational mother had a womb for rent.

Nevertheless, they all went to court to clear up the question of parenthood before delivery. There, a Detroit judge ruled that the genetic mother and father would be the real parents of the baby in the other mother's womb.

Is this beginning to sound like something out of Gilbert and Sullivan? "Brave New World"? Does it remind you of Margaret Atwood's "The Handmaid's Tale"?

Slowly, one step at a time, we have been separating reproduction from sexual intercourse. Artificial insemination, in vitro fertilization, surrogate motherhood. Now, in logical sequence, we have the surrogate motherhood of an in vitro fertilization. It requires a very tiny leap, more of a hop, to imagine a future embryo created from sperm donor and egg donor, implanted into a second woman, all for adoption by a third.

Who is the mother in that case? The one who provided the genes, the one who supplied the womb or the one who set up the whole project in order to raise the child? We have never before had so many motherhood options. More to the point, we have never before said that a woman who just gave birth to a baby is not its mother.

I am uncomfortable enough with a technology that reduces the pregnant woman to the status of a commercial vessel carrying genes to term for her employer. I am more uncomfortable when the courts take the motherhood title away. If the egg donor is the "real" mother, then she might even win the right to protect her embryo if the "vessel" was smoking, or eating improperly, or resisting medical treatment.

The situation is even more unnerving from the point of view of the baby, who has come from the egg and out of the womb. For two or three days, Baby Girl Who was in a legal limbo while the physicians did tests to confirm that the baby was the offspring of the genetic parents. She was born a motherless child.

"It's intolerable to have a newborn baby and not know who its parents are," says medical-ethics lawyer George Annas of Boston University, "If the question is what's best for the child, I would argue for the gestational mother. You know who that is. There is never any question in anyone's mind."

The presumption that the woman who carried the baby is the mother is common law in most states. It should be everywhere. The genetic parents can always adopt the baby. It may sound odd to adopt your own genetic offspring -- what if the woman decided to keep Baby Who? -- but it is the lesser risk.

All of these quandries, like the babies themselves, are born as we attempt an end run around nature. We don't accept limits, even the limits of fertility. Men and women who cannot conceive or carry children expect science to figure out a way for them to have babies, even their "own" babies. Science is most obliging.

By now, we are so far removed from nature that we need a law to determine motherhood. How odd that we find ourselves arguing about the definition of the very first word in any baby's vocabulary: "Mama."