Preimplantation Genetic Diagnosis
Testing your embryo before it's in utero
Williams goes on to explain that while the risk to the embryo is “very, very low” the greater risk is misdiagnosis when embryologists are attempting to screen for random genetic differences instead of focusing on a specific gene or chromosome suspected of having a problem. Why? Research shows that 40 to 60 percent of all embryos contain some chromosomal flaw, many of which are resolved by the embryo itself. Just as a human body attacks foreign or damaged cells to ward off disease, an embryo can do the same. Williams explains, “You can biopsy an eight-cell embryo and find an abnormal cell. But embryos correct problems, so if seven of the eight cells are normal, the seven good ones will kick out the bad one and continue to grow.”
The ability to pick and choose children according to their genetic make-up opens a Pandora’s box of ethical dilemmas. One debatable topic is the practice of creating embryos for the sole purpose of having a child of a particular gender. Many fertility specialists draw the line at sex selection and choose which embryos to implant based on their size and health. Such was the case with Amanda. “I produced six eggs,” she says. “Three were duds and three fertilized. One of the three embryos tested positive for cri-du-chat. The doctors transferred the remaining two into my womb and one grew. Today we have Caroline.”
Other fertility specialists see no problem with sex selection and advertise their expertise in what’s known as “family balancing.” Doctors like Peyman Saadat, MD, medical director of the Tyler Medical Clinic in Beverly Hills, California, helps fertile women, with no medical reason to create embryos outside of the womb, select the gender of their children using PGD. “I have a patient now who wants a girl first,” he says. “She only wants to be pregnant once and wants it to be girl.” Saadat says the desire for boy or girl is sometimes culturally driven, but that the requests for both genders are about even.
The future holds other interesting scenarios. By removing a cell from a new embryo, scientists can now save its entire DNA onto a microchip and determine thousands of characteristics including the child’s hair color, eye color and height. This technology isn’t available to the public yet, but it’s currently in development. If some parents prefer to create, test, and discard embryos to get a boy or a girl, might they also do the same to add a tall red-headed boy or petite blond girl to the family? Might insurance companies decline to cover certain families because a person’s embryonic DNA revealed a predisposition for a disease like breast cancer or leukemia? Will Congress enact legislation governing the use of embryonic genetic testing as they’ve done for cloning and stem cell research? Only time will tell.
Although PGD is not a guarantee of a perfect baby or a lifetime insurance policy against disease, it is a fascinating scientific tool that enables many couples to prevent heartbreaking medical conditions in their children. If you’d like to find out if you’re a candidate for PGD, contact a fertility specialist in your area to see if it’s the solution to help you build your family.
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