But to those who believe that life begins at conception – even if it takes place in a petri dish – there is no difference. In a 2006 submission to Health Canada, the Catholic Organization for Life and Family called for a ban on PGD, saying it “inherently disrespects the dignity and worth of human life, since it is performed in order to select the most genetically perfect embryos while discarding those that are deemed undesirable.
“Parents, doctors and society become ... the arbitrators of life or death.”
PGD parents wrestle with ethical implications
The idea that they may be playing God has not escaped those who have tried PGD, or thought about trying it. The topic makes many parents uncomfortable – several couples turned down requests for interviews, including Canadians among Dr. Steinberg's clients in Mexico.
But many are more candid with the anonymity provided by online fertility forums. For instance, an Australian mother of two sons recently wrote that she had intended to use screening to have a daughter but had a last-minute change of heart – “PGD felt too much like I was playing God,” she said, adding, “I know I'm pregnant with a girl. Don't know how I know but I just do.”
Another woman, who had used PGD to avoid passing down a syndrome that results in severe facial deformities, countered that she “doesn't really get the playing-God argument. ... I think IVF is unnatural – but so is driving a car.”
A 47-year-old woman who had relied on donor eggs, and underwent IVF and PGD intending to conceive a boy as the fifth-generation namesake in her husband's family, said: “I don't feel that we are playing God at all. ... No one but God can decide what sex the embryos are going to be.” Indeed, all her healthy embryos turned out to be girls.
About the same time that Dr. Steinberg was riling the Pope, Health Canada asked Dr. Nisker to find out how Canadians were using PGD, which led to a 2009 study that he says is already out of date. But he and sociologist Susan Cox of the University of British Columbia revived Orchids for a national tour, quizzing audiences to get an idea of how Canadians feel about the technology.
Of the 950 respondents, he says, “most were worried that government or doctors would draw the line around what could be tested. People were happier with everyone drawing their own lines, even if they were also worried about what would happen to the disabled.”
In fact, despite his own fears and 15 years of pushing for regulations, Dr. Nisker agrees that universal limits are tough to set, given that PGD is also embedded in the freedom of reproductive choice.
As Prof. Dickens, the U of T expert in reproductive law and bioethics, explains: “It is not clear that the government can, or should, intervene.”
In some cases, PGD can be seen as a public-health triumph, he says, citing its profound effect on Ashkenazi Jewish communities that have a high risk of passing on Tay-Sachs, a neurodegenerative disease that usually kills a child by the age of 4.
If both parents carry the gene, chances are one in four their child will be afflicted. Two carriers used to be advised not to marry, or relied on amniocentesis and abortions. (A prenatal screening program of this type helped to reduce Tay-Sachs in Montreal's Jewish and Mediterranean communities by more than 95 per cent.)
But with PGD, couples can take evolution into their own hands, implanting embryos not only free of the disease, but those that carry no copies of the defective gene at all – eliminating the risk of Tay-Sachs to future generations.
And while Prof. Dickens agrees that using PGD for cosmetic traits rather than life-and-death conditions is “questionable,” he doesn't rule it out. “If this is being funded by the individual, it is hard to limit.”
Unlike the U.S. and Canada, Britain strictly regulates genetic selection, permitting it only for inherited disorders deemed serious enough to warrant discarding embryos that carry them. Every addition to the test list requires formal permission and, to date, 130 have been approved.