MicroSort

What it is

A dye technique that attempts to segregate girl-producing sperm from the boy-producing variety. Sperm of the desired gender is inserted directly into your uterus, usually via artificial insemination (AI).

Effectiveness

The method is about 90 percent successful when it comes to choosing girls and about 74 percent successful for boys. These rates are per pregnancy, not per cycle.

How it's done

MicroSort is based on the premise that girl-producing sperm, which carry X chromosomes, are bigger than the boy-producing sperm, which carry Y chromosomes. The procedure involves coloring a sperm sample with fluorescent dye and then zapping it with a laser that illuminates the dye. The bigger X chromosomes absorb more dye and glow brighter than the Y ones. Sperm are then sorted by supposed gender and the preferred sex is transferred to the uterus, usually via AI. In some cases in vitro fertilization (IVF) is used — which may increase the likelihood of a pregnancy but is also more invasive and expensive.

Pros

• Artificial insemination poses virtually no health risks and is cheaper than IVF. But you may have to take fertility drugs, which can cause side effects and increase your chances of having multiples.
• Because the method typically uses AI instead of IVF, you don't have to worry about what to do with extra embryos.
• MicroSort can also be used to try and prevent the transmission of X-linked disorders — diseases that moms carry and can transfer to boy babies but not girls, such as hemophilia and Duchenne's muscular dystrophy. It lowers the risk of transmitting these disorders but isn't 100 percent effective.

Cons

• The procedure is still being tested in clinical trials and hasn't been approved by the Food and Drug Administration.
• Since MicroSort is relatively new (it's been available since 1995 and as of January 2004, more than 500 pregnancies have been achieved), little is known about possible risks.
• MicroSort can't guarantee a specific gender because the technology doesn't completely exclude sperm of the unwanted sex.
• The pregnancy rate for each artificial insemination cycle is modest — 16.6 percent. With IVF, the pregnancy rate is 33 percent.

Cost

Approximately $3,000 per treatment cycle if AI is used. IVF adds an average $12,400 to the cost of each cycle.

Availability

To qualify for MicroSort's program, you must be married and have at least one child and want a child of the opposite gender. You, or your egg donor, must be 39 or younger.

There are two MicroSort centers: The Genetics and IVF Institute has a MicroSort clinic in Fairfax, Virginia. Telephone: (800) 277-6607. The second clinic is in Laguna Hills, California and operates in partnership with the Huntington Reproductive Center. Telephone: (866) 472-4483.

MicroSort patients who opt for AI must undergo the procedure at one of these two facilities. But if MicroSort is carried out with IVF or PGD, sperm samples can be processed at one of the labs and then shipped to a collaborating medical facility. If you're interested in exploring that option, talk to your doctor.