It's not easy being male. Research shows men are naturally programmed to check out early — at least sooner than women.
Recent analysis by researchers at the University of Michigan showed that three men die for every woman during the years between adolescence and adulthood. In the broader view, 16 men die for every 10 women before the age of 50.
What's so hazardous about being male? Researchers believe it ultimately has to do with early programming and the other sex, or, rather, pursuit of them.
"There's a reason why there are societal expectations for men to be tough," said Daniel Kruger, a social psychologist at the University of Michigan Institute for Social Research and lead author of the study appearing in a recent issue of Evolutionary Psychology. "What happens is the behavioral tendencies that we're selected for in early history is still with us today."
Here's the idea: When it comes to reproduction, female mammals (including women) make a huge physical investment. Being pregnant consumes calories and energy that would normally be used for self survival. Then there is the danger that mothers face during childbirth and the costs of caring for young after they're born (for most mammals the mother is the primary caregiver).
Males, on the other hand, have minimal costs when it comes to reproducing. Because the cost is relatively low, males typically try and mate as much as possible. The trick, then, lies in convincing females to mate and this means beating out other males for the role. That means being aggressive and doing things that may not be great for personal survival, but helps gain status and win female attention.
"Basically the idea is men front end all their risk because it's important to reproduce early and often," said Benjamin Campbell, an expert in anthropology at Boston University.
Times have changed, of course, at least for humans living in developed countries. Childbirth isn't nearly as risky as it once was. Many men play equal roles in taking care of children and most men don't father children of several women.
Nonetheless, Kruger says behavior stemming from early man's dog-eat-dog days remains in our systems. And that's bad news for men. Kruger figures more than 375,000 lives would be saved each year in the United States if men's risk of dying were as low as women's.
"You see a greater tendency for risky behavior among men," said Kruger. "Men are predominantly the ones getting themselves into trouble."
Using data from the National Center for Health Statistics, the World Health Organization and the Human Mortality Database, Kruger and his University of Michigan colleague, Randolph Nesse, showed that men had higher death rates than women for all 11 leading causes of death in the United States.
The difference between male and female deaths peaks during young adulthood from ages 20 to 24, when three times as many men die as women. Among causes of death, the biggest differences between male and female mortality rates were for suicide, then homicide, followed by non-automobile accidents and then automobile accidents.
"You would think the peak would be among teenagers when testosterone levels are rising rapidly," said Campbell. "The fact that it peaks during young adulthood suggests it might be directly related to competition for females."