Scientific progress is remaking the debate around abortion. When the U.S. Supreme Court decided Roe vs. Wade, the case that led the way to legal abortion, it pegged most fetuses’ chance of viable life outside the womb at 28 weeks; after that point, it ruled, states could reasonably restrict women’s access to the procedure. Now, with new medical techniques, doctors are debating whether that threshold should be closer to 22 weeks. Like McGuire, today’s prospective moms and dads can learn more about their baby earlier into a pregnancy than their parents or grandparents. And like McGuire, when they see their fetus on an ultrasound, they may see humanizing qualities like smiles or claps, even if most scientists see random muscle movements.

These advances fundamentally shift the moral intuition around abortion. New technology makes it easier to apprehend the humanity of a growing child and imagine a fetus as a creature with moral status. Over the last several decades, pro-life leaders have increasingly recognized this and rallied the power of scientific evidence to promote their cause. They have built new institutions to produce, track, and distribute scientifically crafted information on abortion. They hungrily follow new research in embryology. They celebrate progress in neonatology as a means to save young lives. New science is “instilling a sense of awe that we never really had before at any point in human history,” McGuire said. “We didn’t know any of this.”