A man's testosterone level drops by about half just after having a child, which physiologically makes him much more interested in caring for a family than in mating. These findings challenge traditional beliefs that child-rearing is just for women, because it demonstrates that women are not the only ones who are biologically adapted to be parents. The levels go back up some as the child grows, but they can still be down by one-third for as long as five years after the child is born.
More facts about testosterone:
- As men become adults, they experience significant increases in testosterone. This makes them more prone to aggressive behaviors, helps with sperm production and generally increases behaviors that attract a mate. After they succeed at this — physiologically demonstrated by producing offspring — the elevated testosterone levels are no longer needed, at least for a while.
- Although many people think of testosterone as only a male hormone, women have testosterone, too. It helps increase a woman's sex drive, but too much of it can cause a deepening voice, acne, anger problems and irregular menstruation. Some women take testosterone to help with the symptoms of menopause, but as of 2011, there was not enough evidence for it to be a widely recommended treatment.
- Lower testosterone levels in men after their children are born are thought to be beneficial for both the couple's relationship and the child, because it makes the man less likely to cheat and more likely to stay with the child's mother long-term. Biologically speaking, this is an advantageous situation for the offspring.