What Science Says About Abortion

Overturning Roe won’t stop states from tying abortion access to fetal viability

- By David H. Freedman

THE ESSENCE OF THE SUPREME Court’s 1973 Roe v. Wade decision, which established a woman’s right to an abortion, was to balance a pregnant woman’s constitutional right to privacy with the hypothetical rights of a fetus that at some point might be considered a person, even while inside the womb. The Court’s compromise was to confer those hypothetical rights on a fetus when it reaches the 28th week of pregnancy.

That threshold wasn’t arbitrary; it was based on the state of medical science at the time. In 1973, doctors and midwives were sometimes delivering babies prematurely at 28 weeks—but no earlier. Clinical experience established when a fetus could be considered just developed enough to live outside the womb.

In the half-century since, the science of fetal development and early birth has advanced considerably. Neonatal physicians and researchers have modified their thinking on when a fetus is and isn’t viable outside the womb, on how it makes the transition from a bundle of cells to a thinking, feeling being, on the relationship between a fetus and the health of the mother and on the many factors that determine whether a particular premature birth will be successful.