Scientists have long treated homosexuals as people whose bodies and actions are badly in need of explanation. One way scientists have tried to explain homosexuality is via appeal to evolutionary theories. Most of these intellectual efforts have been aimed at showing homosexuality to be a sign of deviance or degeneration-that is, as an evolutionary evil. Lately, however, a number of theorists have instead been interested in imagining why homosexuals could be good for the human species, evolutionarily speaking. As Vernon Rosario has noted in Science and Homosexualities, regardless of this political shift, the basic goal has remained the same, namely, to make sense of homosexuality via “final causes”—that is, via appeal to evolution.