Getting married saps your testosterone | being-human | 18 October 2007 | New Scientist Space
The progressive lack of interest in sexual activity that follows marriage seems to have a biological basis. This study of Ariaal men in Kenya shows that testosterone levels in men decline as they take on additional wives. It seems as if the need to reproduce exerts a profound influence on testosterone levels in men, though this need alone does not account for the fact that having more wives results in greater declines in testosterone levels.