One gender difference that has not received much attention, perhaps due to the political landscape of the last half century, is that it is harder to be a man than it is to be a woman, at least in terms of existence and survival, the very basics of the game of life. Male foetuses are more likely to spontaneously abort, die at birth, die in childhood, die as young adults, die at – well males are more likely to die than females at virtually any age – at least in rich, Western democracies.
Sadly, more insidious cultural, political, and social factors influence the gender ratio in other parts of the world, often to the detriment of women. But in the absence of any deliberate attempt to alter nature, males have a higher mortality than females at all ages. Then how does nature ensure that there are enough males? Well, in actual fact, males are more likely to be conceived than females, and more males are born than females. So, nature corrects for the vulnerability of men by making more of them.
Men are far more likely to suffer from 290 X-linked recessive maladies, because they only have one chance of receiving the dominant (non-disease causing) gene. The Y chromosome doesn’t give them the second chance that women have. Some of the potentially fatal conditions are Duchenne’s muscular dystrophy, agammaglobulinemia, adrenoleukodystrophy, and severe combined immunodeficiency, but there are many, many others in the list of 290 that are exceedingly unpleasant if not lethal. And if genetically-based diseases don’t kill a male, microbe-based diseases are more likely to be lethal. The female immune system fights more pathogens more effectively than the male immune system. This is true in humans and in rats.
Indeed, being male is a deadly gamble in a variety of species. In the animal kingdom females generally outlive males. This is true of arachnids (where she often eats him for supper!), many species of birds, crustaceans, various invertebrates, seals, sheep, and cattle. Only in certain species of fish and bird does research provide an example of males outliving females; but the rule is that she will outlive him.
Over the course of the 20th century, as overall life expectancy has dramatically increased in rich Western democracies, the gender gap in longevity has also increased. Women have benefited more than men, because the gains in longevity have largely been due to the eradication of diseases (i.e., internal factors) and birthing of children. This suggests that it is the external factors which remain and have a strong influence on the gender difference in terms of health and mortality.
Women outlive men in rich countries because men do things that have lethal consequences. Men disproportionately die from accidents (automobile, military, occupational, etc.) and destructive behaviours (smoking, alcohol, drugs, etc.). The very act of survival seems to be more of a challenge for men. Indeed, men take more risks than women in general, something we’ll discuss in greater detail when we examine which sex is indeed lousier at driving. Men also perceive less danger and risk in a given circumstance, suggesting that not only are men willing to take greater risks than women, but they are also less aware of the risks they do take. Even the use of drugs reflects the male tendency to take risks. She takes legal drugs prescribed by doctors; he takes illegal drugs prescribed by pushers.
From an evolutionary perspective, it’s reasonably easy to see why nature would create such fragile, risk-prone men. Let’s start with a population of 1000 males and 1000 females in some hypothetical culture. If 999 males died for some reason, 1000 new babies could be added to the population in the next year, greatly increasing the species’ survival prospects (and what a lucky boy he would be!) But if 999 women died for some reason, only 1 new person could be added to the population in the next year (and how many men would die or be seriously maimed fighting for the opportunity to be the father!) One little accident or deadly microbe and the whole species would be wiped out, regardless of how many men were left. Nature seems to have made men the “expendable sex”, providing them with an mortality-prone biology and a deadly behavioural repertoire. So what’s the benefit of having all these fragile but dangerous men around? You’ll have to check back next month for the answer! How’s that for a cheap teaser?