“We Don’t Want to Know What Will Kill Us: Years of Data on Genetic Testing Reveal That When given the Option, Most People Want Less Information, Not More”, 2017-09-27 (; backlinks; similar):
In the three decades since the first predictive genetic tests became available, a great deal of data has accumulated to show how people respond to knowing previously unknowable things. The rise of genetic testing has presented scientists with a 30-year experiment that has yielded some surprising insights into human behavior. The data suggest that the vast majority react in ways that at first seem counterintuitive, or at least flout what experts predicted. But as genetic testing becomes more widespread, the irrational behavior of a frightened few might start to look like the rational behavior of an enlightened majority. Doctors’ repeatedly failed attempts to anticipate people’s responses to genetic testing is not for want of preparation. Starting in the 1980s, they conducted surveys in which they asked how people might approach the test, were one available. They noted the answers and planned accordingly. The trouble was, when the test became a reality, their respondents didn’t do what they had said they would.
…In those preparatory surveys, roughly 70% of those at risk of Huntington’s said they would take a test if it existed. In fact, only around 15% do—a proportion that has proved stable across countries and decades. A similar pattern emerged when tests became available for other incurable brain diseases…Prenatal genetic testing is widely available, but the uptake by expecting couples in which one partner is a known carrier of an incurable disease is even lower than that of testing among at-risk adults. Most opt to have a child whose risk of developing that disease is the same as theirs was at birth. Why do people act in this seemingly irresponsible way with respect to their offspring?
A unique longitudinal study published in 2016 by Hanane Bouchghoul and colleagues at the Pitié-Salpêtrière Hospital in Paris unpacks that decision-making process. They interviewed 54 women—either Huntington’s carriers or wives of carriers—and found that if a couple received a favorable result in a first prenatal test, the majority had the child and stopped there. Most of those who got an unfavorable result terminated the pregnancy and tried again. If a second prenatal test produced a “good” result, they had the child and stopped. But if it produced a “bad” result and another termination, most changed strategy. Some opted for preimplantation genetic diagnosis, removing the need for termination, since only mutation-free embryos are implanted. Some abandoned the idea of having a child altogether. But nearly half, 45%, conceived naturally again, and this time they did not seek prenatal testing. Summarizing the findings, the geneticist on the team, Alexandra Dürr, says, “The desire to have a child overrides all else.”
…In a study that has yet to be published, Tibben has corroborated the French group’s conclusion. He followed 13 couples who, following counseling but prior to taking a prenatal test, agreed they would terminate in the case of an unfavorable result. None of them did so when they got that result. “That means there are 13 children alive in the Netherlands today, whom we can be 100% sure are [Huntington’s] carriers”, he says.