We all know the drill for reproduction—sperm meets egg. But mice aren’t people. And the same recipe doesn’t work for human reproductive cells. One reason, according to Dr. Mitinori Saitou at Kyoto ...

Researchers at Newcastle University in England report they have coaxed the first human sperm cells from embryonic stem cells, in a remarkable demonstration of how quickly the field of stem-cell ...

A team of scientists has created synthetic human embryos from stem cells, without the need for either an egg or sperm — a remarkable breakthrough that raises plenty of thorny ethical questions. While ...