WASHINGTON (AP) — Researchers have performed the first known transplant of sperm-producing stem cells in hopes of restoring fertility in a man who survived childhood cancer. There’s no proven way to preserve boys’ future fertility if cancer strikes before puberty. But a University of Pittsburgh study for years has frozen testicular tissue and cells before boys begin treatment to see if they eventually might help. Now the first study participant has returned as an adult to reimplant those cells in hopes of one day fathering a biological child.… Continue Reading