Scientists have been successful in creating an “artificial womb” that appears effective at enabling very premature fetuses to develop normally for about a month. So far the device has only been tested on fetal lambs, but Alan Flake, a fetal surgeon at Children’s Hospital of Philadelphia who led the study published in the journal Nature Communications, says the group hopes to test the device on very premature human babies within three to five years. “If you can just use this device as a bridge for the fetus then you can have a dramatic impact on the outcomes of extremely premature infants,” Flake says. “This would be a huge deal.”

Some, however, find the advance unsettling and are already voicing concerns about the impact it would have on the political debate about abortion. Dena Davis, a bioethicist at Lehigh University,  worries about whether this could blur the line between a fetus and a baby. “Up to now, we’ve been either born or not born. This would be halfway born, or something like that. Think about that in terms of our abortion politics,” she says.