Higher mortality rates in men could have a biological explanation, an analysis of existing data suggests. By reviewing figures from the Centers for Disease Control and Prevention (CDC), researchers have determined that men face a much higher risk of dying as a result of violent accidents as well as serious illnesses. The findings thus indicate that the disparity between male and female longevity is not strictly behavioral, and that a genetic factor may be to blame.

"What is surprising is that the pattern of excess male mortality exists across such a broad range of diseases and at all ages," senior author Chris Feudtner said, speaking to Reuters Health.

While accident- and injury-related deaths have long been ascribed to dubious judgment, overestimation of abilities, and poorly conceived guy stuff, the universality of the pattern suggests that there may be a hormonal or genetic explanation for male vulnerability and female robustness. According to Feudtner, a combination of biological and environmental factors would explain why the higher mortality rate persists through such diverse contexts and age groups. In addition, it would help us understand men’s disproportionate infant mortality rate.

“The infant mortality rate is due to a wide variety of congenital malformations and genetic or metabolic conditions, as well as problems that occur during the process of being born, and then the risk of death goes down until it starts to rise again, mostly due to rising risk of external causes of death like car accidents and violent injuries,” Feudtner explained.

One explanation may be the chromosomal makeup of males. In their reports, the researchers point out that the X chromosome contains 836 active protein-coding genes. The fact that men only have one such chromosome problematizes DNA repairs and raises their likelihood of developing diseases caused by recessive genes. In addition, genes tend to exhibit gender-specific behavioral patterns, and may simply provide better protection in female organisms.

“The potential genetic and hormonal mechanisms for the mortality difference between males and females warrant investigation,” the researchers concluded.

Perhaps male hubris isn’t always to blame, it would seem.

Source: Pediatric Mortality in Males Versus Females in the United States, 1999–2008. Sheri L. Balsara, Jennifer A. Faerber, Nancy B. Spinner, and Chris Feudtner.Pediatrics peds.2013-0339; published ahead of print September 2, 2013, doi:10.1542/peds.2013-0339