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A way to choose a baby's gender

The technique gains attention, appealing to couples who have a medical reason or a personal preference. Some doctors oppose it on ethical grounds.

March 03, 2003|Shari Roan | Times Staff Writer

Once they decided to have children, MiShel and Carl Meissner tackled the next big issue: Should they try to have a girl?

It was no small matter. MiShel's brother had become blind from a hereditary condition in his early 20s, and the Meissners had learned that the condition is a disorder passed from mothers to sons. If they had a boy, he would have a 50% chance of having the condition. A girl would be unaffected.

The New Hampshire couple's inquiries about gender selection led them in 1999 to Fairfax, Va., where a new sperm-separation technique, called MicroSort, was under investigation. The couple's first attempt at artificial insemination, using sperm sorted by sex chromosome, was a failure. But on the second attempt a few months later, MiShel became pregnant and gave birth to a daughter. They will try to have a second daughter using the technique later this year.

"I probably would not have had children if not for MicroSort," she said. "This was pretty much our only option for kids."

The technique separates sperm into two groups -- those that carry the X-chromosome (which leads to a female baby) and those that carry the Y-chromosome (which produces a male baby). The process was developed in the early 1990s by the Genetics & IVF Institute in Fairfax, and last week's opening of a MicroSort laboratory in Laguna Hills marks the company's first expansion.

"We believe the number of people who want this technology is greater than those who have access to it," said Dr. Keith L. Blauer, the company's clinical director.

The expansion brings with it not only a seemingly effective way to select a child's gender -- it also highlights a host of ethical and practical considerations that accompany sex selection, especially for the majority of families who use the technique for nonmedical reasons.

The Laguna Hills clinic, which is a joint effort with the Huntington Reproductive Center of Southern California, offers sex selection for two purposes: to help couples avoid passing on a gender-linked genetic disease and to allow families who already have a child of one gender "balance" their families by having a baby of the opposite sex. (More than 500 X-linked diseases, such as Duchenne muscular dystrophy and hemophilia, are passed from mothers to sons.)

The technology is still experimental; couples using the method will do so as part of a clinical trial overseen by the Food and Drug Administration. However, Blauer says the company has impressive success rates; 91% of the women who become pregnant after sorting for a girl are successful, while 76% who sort for a boy and get pregnant are successful. Couples hoping for a girl are nine times more likely to get a girl compared with natural selection, while those desiring a boy increase chances by threefold.

Fertility experts agree that the technique is significantly different from other sex-selection methods, some of which they describe as little more than "voodoo." They include sex-selection diets (eating salty foods supposedly increases the chances of having a boy), an ancient Chinese birth calendar that suggests timing conception to a particular time of the year and the more common sperm-spinning methods that many infertility clinics offer today. The spinning technique uses centrifugal force to try to separate sperm. But most doctors say the method is hardly better than the 50-50 chance nature provides.

"The success rates for these other methods are not good," said Dr. Larry Lipshultz, a professor of urology at the Baylor College of Medicine, in Houston. "They are very comparable to flipping a coin."

The new technique separates sperm based on the fact that the X chromosome is larger than the Y chromosome. A machine is used to distinguish the size differences and sort the sperm accordingly. The result is then checked using another type of DNA analysis to ensure that it contains mostly X- or Y-bearing sperm. The desired sample is then used for artificial insemination or in-vitro fertilization.

But even this gender-selection process is not as accurate as a post-conception technique called pre-implantation genetic diagnosis. In that, doctors create embryos using in-vitro fertilization. A cell is then removed from each embryo and analyzed for genetic characteristics before selected embryos are implanted in the woman's uterus.

Pre-implantation genetic diagnosis is highly accurate when determining gender or the presence of genetic disease, but it is costly and poses ethical dilemmas for some couples.

The Meissners ruled out less scientific approaches as unreliable and were uncomfortable with pre-implantation genetic diagnosis, because that method creates embryos that would go unused, something the couple was uneasy about. "If another person would choose to do pre-implantation genetic diagnosis, fine. But I didn't think I could do it," MiShel Meissner said. "It's a very personal choice."

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