Now that fewer than 50 adult Florida panthers are left in the wild, incest--which can produce offspring with a double whammy of bad genes--is bringing out the worst in them. Many of the cats suffer congenital heart problems, and 90 percent of the males have at least one undescended testicle, which decreases their sperm count. To give the panther population an infusion of healthy genes, biologists this past year released eight female cougars from Texas into three southern Florida parks. Cougars and panthers belong to the same species; only geography separates them--that and the fact that the cougar population is healthy. Our goal is for these eight females to produce kittens that have a father that is a Florida panther, says biologist Kenneth Johnson of the Florida Game and Fresh Water Fish Commission. Sometime in 1996 he and his colleagues should know whether the cats are cooperating