6 core challenges that researchers must consider as the race to create models that are ever closer to real human embryos heats up.

Frozen embryos are filling storage banks around the world. It's a struggle to know what to do with them. Lisa Holligan already had two children when she decided to try for another baby. Her first two ...

Scientists are exploring ways to mimic the origins of human life without two fundamental components: sperm and egg. They are coaxing clusters of stem cells – programmable cells that can transform into ...