Preimplantation genetic diagnosis (PGD)

What it is

An in vitro fertilization (IVF) technique in which embryos are created outside the womb and then tested for genetic disorders and gender.

When PGD was introduced back in 1989, it was used solely to help couples or individuals with serious genetic disorders reduce their risk of having a child who suffered from the same condition. Today PGD is still used for this reason, but is also used commonly when women are 35 or older and/or have a history of recurrent miscarriage. Only a handful of clinics offer the technique for sex selection for nonmedical reasons.

Effectiveness

Almost 100 percent effective.

How it's done

During an IVF cycle, eggs are fertilized with sperm in a petri dish. A single cell or cells are later removed from each of the resulting 3- to 5-day-old embryos and tested for gender.

In a regular IVF cycle scientists try to determine which embryos are normal merely by looking at them under a microscope. But with PGD, the embryos of the desired sex are tested thoroughly for genetic abnormalities. By transferring only healthy embryos to the uterus, you're less likely to miscarry or have a child with a genetic disorder. Prenatal tests such as amniocentesis or chorionic villus sampling (CVS) are still recommended if you're 35 or older because more genetic abnormalities can be detected later in pregnancy.

In a regular IVF cycle, doctors usually transfer two or more embryos to your uterus — the number depends on your age, the quality of the embryos, and your reproductive history. (If you're 40 or older, typically four or five embryos may be transferred.) But in PGD, doctors transfer no more than two because they've already weeded out embryos that are unlikely to implant or to result in a healthy pregnancy.

Pros

• If you do get pregnant, PGD guarantees with almost 100 percent certainty that you'll have a baby of your desired gender.
• Following a PGD cycle, remaining embryos of the selected gender are automatically frozen. These can used in another attempt, if you miscarry or if you decide you want more children down the road. Frozen embryo transfers aren't as successful as fresh transfers, but the procedure is less invasive and significantly cheaper.

Cons

• A single round of PGD can cost nearly $20,000.
• The procedure is invasive and the removal of eggs from your ovaries can be painful.
• The fertility drugs you have to take can have uncomfortable side effects such as weight gain, bloating, swelling, or blurred vision.
• As with any IVF pregnancy, you're more likely to have multiple births. According to the latest statistics from the Centers for Disease Control and Prevention, 46 percent of infants conceived as a result of IVF and related procedures were twins.
• Only one in three fresh IVF cycles results in a live birth, and that figure decreases as you get older. But some doctors claim higher success rates with PGD because defective embryos are excluded.
• You'll need to decide what to do with the embryos of the undesired gender: freeze, destroy, or donate for other couples or research.

Cost

IVF cycles cost an average of $12,400. PGD adds an additional $3,000 to $6,000-plus to the tab. Check with your medical insurance company — part of the expense may be covered.

Availability

Most fertility clinics that provide PGD don't allow it to be used solely for sex selection. You must have a medical reason such as a family history of genetic diseases or repeat miscarriages, or be over a certain age, usually about 38, to qualify for the procedure.

That said, a few centers allow you to use PGD to choose the sex of your baby even if you don't have a medical reason to do so:

• Genetics and IVF Institute, with facilities in Virginia and Maryland. (To qualify, couples must be married, have at least one child, and desire a child of the opposite gender.)
• The Sher Institutes for Reproductive Medicine, with seven branches nationwide. (Prospective patients are screened on a case-by-case basis, and couples with no children are not excluded from consideration.)
• Reproductive Specialty Center in Newport Beach, California (restricted to couples who have at least one child and desire a child of the opposite gender).

For more information

Read the American Society for Reproductive Medicine's report on sex selection and recommendations for its use.