For a couple like Kristen and John Magill of Grafton, Massachusetts, having a boy became important after welcoming three little girls into the world. John is a "junior," Kristen explains, and they have a family business they'd like to continue in the family name.

Can the Magills choice the sex of their next baby? Should they be able to?

Sex selection has become a hot topic not only because of the legal and ethical and legal issues involved but also for where it is available. The United States remains one of the few places in the world where the procedure is not regulated, and so, couples come here from Australia, Canada, China, the Czech Republic, England, Germany, India, Japan, Mexico, New Zealand, Switzerland and other countries where the practice is banned.

Who is right—the United States or most of the rest of the world?

A discussion of these questions requires first understanding the medical process involved.

How does sex selection work?

There are two main laboratory techniques through which couples can increase their chances at having a baby with the sex of their choice; note that clinics, though, have requirements on who is eligible for treatment. For instance, most require a married couple (the woman over a certain age, usually 38) who already has at least one child of the "unwanted" sex. Also, fertility drugs are almost always involved.

The more expensive of the two, Preimplantation Genetic Diagnosis (PGD), involves creating embryos through in vitro fertilization (IVF) outside the womb and then implanting only healthy embryos of the chosen sex in the woman's uterus. Although one round of PGD can cost up to $20,000, you are almost guaranteed to carry the sex of your choice—accuracy hovers around 100%. Unused embryos (of either sex) may be frozen and used in case of miscarriage or for another pregnancy.

Note, though, that many fertility clinics that offer PGD do not allow its use for sex selection only, requiring some underlying medical reason. While many agree that PGD can be useful for screening out potential diseases, Yury Verlinsky, director of Chicago's Reproductive Genetics Institute, states his stance plainly: "Sex is not a disease."

The other popular method is MicroSort, which relies on a fluorescent dye that is absorbed more by X chromosomes than Y chromosomes. If a couple desires a boy, sperm containing a Y chromosome will be transferred to the woman's uterus usually through artificial insemination. At $3,000 to $4,000 per procedure, MicroSort's reported success rate for producing the chosen sex differs widely according to various sources—anywhere between 60% and 90%. This method is still in clinical trials and not yet approved by the Food and Drug Administration.

A notable difference between the procedures is that with PGD, there are inevitably unused embryos, whereas with MicroSort, there are no embryos created outside the womb, and therefore, none are left over.

Arguments For and Against

Proponents put sex selection under the umbrella of reproductive freedom, and say that "family balancing" is a valid goal. That is, couples like the Magills should be free to choose whether they would like a boy to join a family of all girls. Advocates also say that the choice of an individual couple harms no one, and that parenthood will be more enriched because natural parental desires are fulfilled.

Opponents say, though, that aside from destroying embryos, sex selection reeks of narcissism, unnecessary use of expensive medical care, and worst of all, "consumer eugenics," where parents may soon be deciding future children's hair and eye color, IQ, or height. On the other hand, Kathy Hudson, director of Johns Hopkins University's Genetics and Public Policy Center notes that this fear is unwarranted because of the "limited role that individual genes play in complex human traits."

Critics also claim that sex selection is a form of discrimination—particularly in places where women are already facing substantial prejudice. South Asian feminists, for example, are against sex selection because of their region's cultural preference for boys, sometimes resulting in female infanticide, abortion of female fetuses, and violence against women who don't give birth to boys.

But Dr. Jeffrey Steinberg of the Fertility Institutes in Los Angeles says that couples who go through PGD there seem to be choosing the sexes about equally—although of his foreign patients, Canadian couples prefer girls and Chinese and Indian couples prefer boys.

Statistics, Professional and Public Opinion

Right now, there is no solid information on how many sex selection procedures are performed and why, but one study suggests that around 3% of PGD procedures have sex selection as the goal, and thousands of healthy, sex-selected babies have been born as a result. And it seems that business is booming as Dr. Steinberg reports that over the past 2 years, requests have increased eight-fold; about 60% of Dr. Steinberg's clients are foreign.

On the professional side, the American College of Obstetricians and Gynecologists and the International Federation of Gynecologists and Obstetricians oppose sex selection for non-medical reasons. However, a 2001 report by the Ethics Committee of the American Society for Reproductive Medicine concluded that the use of PGD should be approved so long as the methods used are safe and effective and doctors have informed couples of the possibility of failure, and the couples have agreed to accept the "wrong" sex.

What does the public think? In a 2005 University of Chicago-Illinois-led survey of infertile women, 41% said they would use PGD if there was no cost involved. Of those, half would pay, with 55% choosing sperm separation like MicroSort and 41% preferring PGD. A survey at BabyCenter.com found that 40% of couples tried methods to select the sex of their child—whether through PGD, MicroSort, or more old-fashioned ways like certain conception positions, timing of intercourse before or after ovulation, or even eating certain foods.

In any event, the debate over sex selection isn't going away any time soon, as in October of 2005, the U.S. government approved a PGD clinical trial; only time will tell whether the United States will remain the unofficial sex selection capital of the world.