Abstract
Reproduction is hypothesized to constrain lifespan and contribute to sex differences in ageing. Various sterilization and contraception methods inhibit reproduction, but predictions differ for how these influence survival, depending on sex, how sex hormones are affected4 and species life history. Here, using data from mammalian species housed in zoos and aquariums worldwide, we show that ongoing hormonal contraception and permanent surgical sterilization are associated with increased life expectancy. These effects occur in both males and females, although the sexes are differently protected from specific causes of death. Evidence of improved survival in males is also restricted to castration, with stronger effects occurring after pre-pubertal surgery. Complementary meta-analyses of published data reveal improved survival with sterilization across vertebrates and increased healthspan in gonadectomized rodents. Improved survival occurs in laboratory and wild environments, and with female sterilization approaches that either remove the ovaries or leave them intact. Reported increases in survival in castrated men resemble the effects in other species, whereas survival of women is slightly decreased after permanent surgical sterilization. Thus the hormonal drive to reproduce constrains adult survival across vertebrates, regardless of the environment in which an animal resides.