Science: Dwindling Breed

Sex and the single gorilla

Poor Omega. Once the pride of the Brookfield (Ill.) Zoo, he is now an outcast. Rejected by two female companions, the hefty 450-lb. gorilla sits alone in his cage, forlornly munching on alfalfa or taking a lackadaisical swing on the rubber tire hanging from his ceiling. Omega's problem is that he is sterile.

Along with chimpanzees and orangutans, gorillas are man's closest kin. They are also remarkably susceptible to human ailments, including mumps, measles, even ordinary colds; and although Omega has never seemed seriously ill, his sperm count is...