CHICAGO (Reuters) - U.S. researchers have found a way to coax human embryonic stem cells to turn into the types of cells that make eggs and sperm, shedding light on a stage of early human development ...

Once a sperm has broken through to an egg cell in order to fertilize it, the two cells need to hold together tightly. This occurs via a type of protein binding that is among the strongest in ...

In the United States, an estimated 645,000 men ages 20 to 50 have azoospermia, a condition in which no sperm are present in their ejaculate. Now, scientists are testing a potential treatment: ...