Recently, a CBS news crew traveled to Iceland, producing a report titled “Inside the country where Down syndrome is disappearing.” As much as it sounds like it, the headline is not clickbait or hyperbole: In Iceland, nearly every women who undergoes prenatal testing and whose fetus receives a diagnosis of Down syndrome decides to end her pregnancy. Each year, according to their sources, only a child or two is born with Down syndrome in Iceland.

Up to 85% of pregnant women in Iceland choose to take prenatal testing. The specific test in question, which CBS calls the “combination test,” takes into account ultrasound images, a blood draw, and a mother’s age to determine the likelihood that a fetus has Down syndrome. (Older mothers are more likely to have babies with Down syndrome because chromosomal errors are more likely as women age.)

In essence, pregnant women in Iceland—and presumably their partners—are saying that life with disability is not worth living. It is one thing to decide that a child who will never walk, talk, feed herself, or engage with caregivers may not have a good quality of life. But children with Down syndrome do not fit this description. If a woman doesn’t want to have a child with Down syndrome, their bar for what qualifies as a life worth living is set quite high. Are babies who are born deaf destined to lead a worthwhile life? What about babies with cleft palates, which can be corrected but leave a visible scar?

Here’s the interesting thing: Down syndrome, or Trisomy 21 as it is also called, is actually one of the less severe chromosomal conditions. Unlike many other trisomies (genetic conditions in which a person has three copies of a chromosome instead of the standard two), it’s compatible with life.

People with Down syndrome have an extra copy of their 21st chromosome, which causes intellectual delays and readily identifiable facial features such as almond-shaped eyes. But the way that Down syndrome expresses itself in an individual can be highly variable. About half of babies born with Down syndrome have heart defects that require surgical correction. Some children with Down syndrome grow up to be adults who go to college and get married; others never live independently.

“Can she live a full life without without ever solving a quadratic equation? Without reading Dostoyevsky? I’m pretty sure she can.”

I have interviewed Amy Julia Becker many times over the years. Becker wrote a book about her daughter, Penny, who has Down syndrome. In A Good and Perfect Gift, Becker, a Phi Beta Kappa graduate of Princeton, chronicles her shift in thinking about intelligence. Pre-Penny, she had assumed that being smart is a prerequisite for being happy and fulfilled. Post-Penny, she changed her mind. “Can she live a full life without without ever solving a quadratic equation? Without reading Dostoyevsky? I’m pretty sure she can. Can I live a full life without learning to cherish and welcome those in this world who are different from me? I’m pretty sure I can’t.”

Deciding what sorts of lives are worth living brings us disturbingly close to the bygone era of eugenics, when only the “right” sorts of people were supposed to procreate.

In 1927, a US Supreme Court decision upheld the right of the state of Virginia to sterilize Carrie Buck, whose daughter, Vivian, was deemed to be “feeble-minded.” Paul Lombardo, a professor of law at Georgia State University who is an expert on eugenics, believes that Vivian was in fact of normal intelligence. Eventually—and fortunately—eugenics fell out of favor, and several US states have issued apologies to people who were forcibly sterilized over the years. Yet the bias against people with disabilities is still very much evident.

When I interviewed Lombardo for my book, The Gene Machine: How Genetic Technologies Are Changing the Way We Have Kids—And the Kids We Have, he noted that there’s a “long list” of physical and mental disabilities that people find discomfiting. At the top of that list? Intellectual disabilities.In other words, Down syndrome and other similar conditions that result in people not being able to pursue a PhD or do quantum physics are often seen as bigger impediments to a “life worth living” than physical impairments. But is that our choice to make for them?

Deciding that people with Down syndrome don’t live worthwhile lives can snowball into a groupthink situation. It will become less and less acceptable to raise a child with Down syndrome, and that will translate into fewer support services available to parents who decide to buck the trend. The lack of support will further encourage women to terminate their pregnancies, leading to even fewer babies born with the condition in the future. If we continue to follow this path, the disappearance of Down syndrome will become a self-fulfilling prophecy. And to what end?