Four million American women are expecting a child this year, and many of them will encounter something entirely new in human pregnancy. Based on a simple blood draw at an initial prenatal visit, they'll be able to learn key genetic information about the fetus they're carrying—and face potentially wrenching decisions about what to do.

These noninvasive prenatal tests, called NIPTs, work by using a sample of cell-free fetal DNA circulating in the mother's blood to detect chromosomal conditions. The tests' most frequent target is trisomy 21, the genetic variation that causes Down syndrome in approximately one in every 700 births in the U.S.

Bioethicists, genetic counselors and advocates for disability rights have nervously anticipated the commercial rollout of these tests. Even—or perhaps especially—those who firmly support reproductive rights know that NIPTs have profound implications.

The tests have the potential to transform women's experience of early pregnancy, reduce the number of people with Down syndrome, and reinforce the assumption that Down syndrome is a dread disease to be prevented. Ultimately, these tests could dramatically reshape our understanding of what it means... see more