Abstract

Studying embryos is important to understanding how humans develop. It can also help us understand some pregnancy complications. But access to embryos is very limited. We wanted to find a way to study embryos without actually needing any! We used stem cells to grow models of blastocysts – young embryos. Our experiments showed that stem cells can form structures that look like blastocysts. We called these models blastoids. 

Blastoids grow and develop at a similar speed as blastocysts. They also have the same size and cell composition. They are not embryos and cannot develop into an organism. But blastoids are a useful way to study human development.