And a few drugs related to myelin production are already in clinical trials, which means that what was once a parlor game—would you take away the Down syndrome?—may one day be a reality for parents like us. If and when drugs are developed that reverse myelin loss specifically in people with Down syndrome, we’ll join the many other parents of children with brain differences who face similar quandaries. There’s the ongoing debate within the autism community, for example, over whether autism is a brain disorder or a mark of “neurodiversity” that ought to be celebrated. There’s the back-and-forth of parents and educators over whether to medicate children with ADHD. And there’s the rise in use of anti-anxiety drugs and antidepressants among children.

In all of these areas, parents face a series of questions about our responsibility in caring for and shaping our children: Are we forming them into the people they want to be, or asking them to conform to a narrow social notion of who they ought to be?

In my first year as a mother, I threw myself into the technical and philosophical literature about disability, eventually encountering the phrase “social construction of disability.” I didn’t understand the concept at first. Disability seemed to me a simple marker of biology. But in books like Michael Berube’s Life as We Know It, a memoir by a father who is raising a son with Down syndrome, I started to see that disability was not as fixed as I had assumed. Without eyeglasses, for example, many more people in our population would be considered disabled—the common challenge of compromised vision has led to technology that enables people to see, even when their biology prevents them from doing so. Similarly, technology has enabled people with prosthetic limbs to walk and climb and run and dance. And for kids like Penny, who have trouble learning math concepts, the problems can be overcome with different teaching approaches. Much of what typical people call disability could just as easily be called difference that society is unwilling to accommodate.

Many individuals with intellectual disabilities once fell so far outside the mainstream of society that they literally lived apart from everyone else. As recently as the 1970s, babies with Down syndrome were routinely sent to institutions shortly after birth. Now they receive “early intervention” through therapy and support at home. Similarly, the Individuals with Disabilities Education Act (IDEA) of 1975 mandated inclusion in public schools for almost all individuals with disabilities, many of whom had been excluded before. Though plenty of progress is still needed, social changes have alleviated much of the suffering and exclusion experienced by people with intellectual disabilities like Down syndrome.

Still, some of the suffering experienced by people with disabilities does not fit so easily into a social-construction model. To give a mundane example: When Penny was 5 months old, we discovered she had hearing loss as a result of fluid in her ears. She was unable to hear and therefore unable to learn how to communicate; she was also in pain from the pressure of all that fluid in her head. We intervened with ear tubes.