By: Yiling Sun

An embryo is a growing baby in the mother’s uterus. It comes from a zygote—or a fertilized human egg—created when a human egg and a sperm meet. Sometimes, the embryo does not survive, but scientists are still trying to discover why.

Jacob Hanna, a developmental biologist at the Weizmann Institute of Science in Israel, is trying to study the details of the embryo and pregnancy.

“We know the basics, but the very fine details we just don’t know,” Hanna said.

Scientists are trying to study embryos to save them. They can only do this by collecting specimens from miscarriages or abortions. Scientists cannot explain why pregnancy fails, but they cannot study much.

Some countries banned this research, but other scientists continued. An embryo can only survive a few days after being created in a lab. Scientists managed to keep it alive for close to 14 days before they destroyed it. Fourteen days was the limit for the country.

The 14-day limit was an obstacle for the scientists because they had to destroy the embryos and could not allow them to live any longer for further study. Scientists considered the possibility of the embryo living past 14 days, but the government made that experiment illegal. Even if it were legal, it would be hard to get the failed specimens since they were rare. So, scientists decided to make models of them in the lab.

Dr. Zernicka-Goetz, a developmental biologist at the University of Pittsburgh, was part of the study as well.

“This was absolutely thrilling,” Zernicka-Goetz said. “It’s sometimes hard to believe that these stem cells are growing into these structures.”

Scientists are still trying to grow embryos for a long time in labs, but the experiment is illegal, and specimens are hard to collect. They hope that the experiment will become legal soon and that they can save dying embryos.