When my husband and I interviewed yet another fertility doctor about his proposed treatment for my recurring miscarriages, we asked him about pre-implantation genetic diagnosis to test whether the embryos we produced through in vitro fertilization were chromosomally normal and therefore less likely to miscarry.
“PGD? You don’t need it,” the doctor said. “Just keep getting pregnant, and if you miscarry, you miscarry. Eventually one will stick.”
I wanted to grab a pair of forceps and forcibly extract his prostate. I had carried a fetus for 5, 7, and 9 weeks and miscarried each time, leaving me a fat, hormonal mess, taking another four months to be ready to get pregnant again. At 42, I didn’t have time to keep getting pregnant; most fertility doctors said I had less than a 10 percent chance of bearing a child through IVF. And I certainly didn’t have time for another devastating miscarriage.
That’s why we wanted to do PGD. The eggs of women older than 40 have abnormal chromosomes 50 to 70 percent of the time, and while many of these eggs do not fertilize or implant in the womb, others result in miscarriages or babies with severe birth defects. Biopsying my embryos to find chromosomally normal ones might not increase my chances of having a baby—after all, there may be no healthy embryos to transfer—but it would reduce my chances of having a miscarriage.
While it’s too early to say whether embryo testing can help older patients with recurrent miscarriage, testing embryos should not be controversial. Genetic tests can identify embryos carrying genes for specific diseases such as Tay Sachs or Gauchers. For parents who are carriers of these diseases—some of whom have already borne afflicted children—PGD can help them have a child who is not going to die.
But that simple message is obscured when the media highlight those who are opposed to such life-saving treatments.
Take “Ethics Questions Arise as Genetic Testing of Embryos Increases,” Gina Kolata’s New York Times article last month, which presented the heartbreaking story of Amanda Kalinsky, who at 26 learned she had the gene for Gerstmann-Sträussler-Scheinker syndrome, a rare neurodegenerative disease “which would inevitably lead to her slow and terrible death,” most likely in her mid-30s to 50s. Her grandfather, great-aunt, uncle, father, and cousins all died from it. Kalinsky decided to put an end to her family legacy and select IVF embryos without the GSS gene. She and her husband now have three healthy children—and two frozen embryos they plan to use—but, Kolata writes, “the procedure also raises unsettling ethical questions that trouble advocates for the disabled and have left some doctors struggling with what they should tell their patients.” The article goes on to question the ethics of discarding unhealthy embryos like Kalinsky’s GSS ones. “Is it acceptable,” Kolata wrote, “for diseases like GSS, that develop in adulthood?”
Or perhaps, as the Wall Street Journal suggested last month, PGD is contentious because it screens out mutations that have “only” a 45 to 65 percent chance of turning into cancer.
“Family With a Risk of Cancer Tries to Change Its Destiny” (subtitled “A Controversial Procedure Lets Couples Select Embryos Free of a Genetic Mutation”) reports that Katie Dowdy had the nerve to have her embryos tested for the BRCA1 gene she carries … even though “the 34-year-old doesn’t have cancer.” No matter that she saw many family members die from breast cancer and has lived with the worry about getting cancer for as long as she’s known she has the gene. “Opponents of PGD for breast cancer also say that having a BRCA-gene mutation doesn't mean a person will necessarily get the disease and that there are options for detecting and treating the cancer,” the story says. (In other words, let your children inherit the disease, and let them treat it, too.)
It seems that as embryo-screening technology improves, the chorus against it gets louder.
I could understand if the concerns were about technique. In the past, a different system, fluorescent in situ hybridization, was used to evaluate the genetic makeup of an embryo by biopsying a single cell of a 3-day embryo, but the technique could not analyze all the chromosomes, occasionally providing false results. The movement today is toward biopsying 5-day embryos using microarray comparative genomic hybridization, which examines all 23 chromosome pairs and provides a more detailed picture of the entire length of the chromosomes. (In both cases, if done properly the embryo develops normally despite the missing cell.)
But that’s not the primary objection. First, critics worry about the use of PGD to choose the sex of the baby. (Although contrary to popular belief, more families in the United States are choosing girls than boys.)
But masses of people are not going to opt for “gender balance” (the fertility clinics’ euphemistic term). If you want to do gender selection, you first have to undergo the painful and costly process of IVF, taking hormones, shelling out tens of thousands of dollars, and then, for genetic screening, you have to add thousands more dollars and more time to store as many embryos as possible. I’m doing genetic screening now to reduce my chance of miscarriage, and trust me, not too many people will voluntarily put themselves through this simply to select a little boy or girl. (The Times cited a 2 percent use of PGD out of 27,000 procedures for gender selection—in other words, 98 percent of the time it is used for other, more serious reasons.)