3D-printed ovaries allowed infertile mice to give birth to pups, a new study reports.

Why it matters: Scientists are focused on creating artificial ovaries in order to restore fertility in women who are sterile due to cancer treatment or disease.

Key point: A supply of healthy ovarian cells is needed to seed the artificial organ — researchers are investigating whether stem cells can be coaxed into ovarian cells in the lab. Further research is also needed to determine whether the 3D-printed structure will work with larger, human ovarian follicles.

Northwestern University researchers 3D-printed a scaffold of biodegradable gelatin then seeded it with ovarian follicles containing immature egg cells. They then removed one ovary from mice and implanted the artificial organ. Previous approaches have been reported but by 3D printing the structural base of the ovary, the researchers were able to get the three main types of ovarian cells to take to the structure. The ovary then connected to surrounding blood vessels, a key to it functioning in the body, and released eggs. The mice mated as normal and three of the seven gave birth to babies that came from eggs ovulated from the implant. The mice fed from lactating mothers, grew up and either gave birth to their own mice or sired offspring.