According to a recent study published in Nature Communications, scientists have developed—and successfully tested—an artificial womb that sustains and nurtures babies born prematurely. The “womb,” essentially a large sandwich bag with tubes, is designed to closely mimic the real thing in all important aspects. The bag is attached to an external machine that pumps in oxygen and nutrients and removes carbon dioxide—just like a placenta. So far, the device has been tested with preemie lambs with reportedly amazing results. According to Alan Flake, lead surgeon on the study, the lambs have exhibited “normal development in every way that we can measure it.” In three to five years Dr. Flake hopes to be testing the technology in human preemies. Here come the ethics questions!