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: ...

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 ...

Jaiwen Hsu was an active 11-year-old when he developed pain in his left knee that forced him to sit out a few soccer games. What his parents thought was a sports injury turned out to be osteosarcoma, ...

Sperm are male reproductive (sex) cells. The word "sperm" can refer to spermatozoon (singular) or spermatozoa (plural). Sperm are tiny cells with an oval-shaped body and a long tail. They measure just ...