

The potential for lab-grown human embryos
Researchers are now permitted to grow human embryos in the lab for longer than 14 days. Here’s what they could learn. It was day 13 in a set of experiments in Ali Brivanlou’s laboratory and he had an agonizing task ahead. His team of developmental biologists had thawed dozens of human embryos, placed them into individual culture dishes and watched them grow through the earliest stages of development — something that only a handful of researchers worldwide had ever seen. But h