An anonymous reader writes "Using stem cell technology, reproductive scientists in Texas, led by Dr. Richard R. Behringer at the M.D. Anderson Cancer Center, have produced male and female mice from two fathers. The study was posted Wednesday at the online site of the journal Biology of Reproduction. The achievement of two-father offspring in a species of mammal could be a step toward preserving endangered species, improving livestock breeds, and advancing human assisted reproductive technology. It also opens the provocative possibility of same-sex couples having their own genetic children, the researchers note."