In 2007, a group of researchers reported a startling discovery: They had created sperm-like cells out of stem cells taken from the bone marrow of human men. Two years later, however, the study was retracted due to charges of plagiarism. Thirteen years later, the ability to create functional human sperm out of stem cells remains elusive.
Scientists have been trying to figure out how to create functioning human gametes — eggs and sperm — from stem cells for 20 or 30 years, says Vittorio Sebastiano, a stem cell biologist at Stanford University whose research focuses on reproductive biology. Doing so would help people struggling with infertility have children and help scientists unlock the secrets of human development. Since 2007, scientists have made considerable progress on this front, creating healthy mouse pups from stem cell-generated gametes and even immature human egg cells. But there is still a long road ahead before scientists will be able to convert skin or bone marrow into babies.
