Mice with artificial, 3-D printed ovaries have successfully given birth to healthy offspring.

It’s another success for members of the same Northwestern University team that in March reproduced an entire menstrual cycle using organs-on-a-chip. This time, they’ve created ovaries from a type of gelatin hydrogel and infused them with immature egg cells before implanting them in female mice. The ovaries behaved like the natural ones, picking out an egg cell to mature and pass along, allowing t