![Nassim Assefi and Brian A. Levine: How in vitro fertilization (IVF) works](https://pi.tedcdn.com/r/talkstar-photos.s3.amazonaws.com/uploads/1ff714d6-cca2-49b1-bfec-cfe5e161bec0/204_invitro.jpg?h=200)
Infertility affects 1 in 8 couples worldwide. But in the last 40 years, more than 5 million babies have been born using in vitro fertilization (IVF). How does it work? Nassim Assefi and Brian A. Levine detail the science behind making a baby in a lab.