For centuries, the idea that females were the biologically weaker sex has been used as a rationale for keeping women submissive and compliant. Evidence suggests, however, that males are actually the weaker sex — at least in the strictest of all terms: death.

Men are more likely to die in utero, in childhood, in adolescence, in old age — in every stage of life, in fact. That’s not just some weird American quirk, or Western European — it’s practically universal. Some scientists go so far as to surmise that men may eventually go extinct.

So is there a way for men from going the way of the dodo?

Bad Genes

A large part of the XY chromosome set’s problems seem to start to be rooted in biology. The Y chromosome that makes a male biologically so is fragile. Females, meanwhile, come equipped with two X chromosomes, so even when there’s a problem in one, the other can step in. Males don’t have this duplicative effect, so if something is damaged in their X chromosome, they’re largely screwed.

Even more alarmingly, the X chromosome is about 1,000 genes long, while the Y chromosome is under 100 genes long and continuing, it seems, to disappear. The odds this leads to the extinction of men in the long term are extremely low, but many think it’s already negatively affecting men’s health today, from infertility to retinal issues.

One study suggested that even a mother’s love can’t overcome this fundamental fragility. When a mom’s body senses it’s carrying a particularly fragile fetus, she’s likely to naturally abort it. It’s probably her body’s way of forcing her to try to conceive another, healthier child. And while this “culling” is all-natural, it seems to mostly target male fetuses.

Chromosomal issues aren’t the only biological quirk that may be contributing to men’s inferior health. Research suggests hormones may be at play, too.

Bad Hormones

Everyone has a bit of testosterone running through their system, but men have a lot more. Curiously, it appears that the higher one’s testosterone, the weaker a man’s immune system. While this makes them less likely to have the autoimmune disorders that plague many women, the testosterone-immune system makes them much more susceptible to infectious disease. Most Americans are lucky enough to avoid infectious diseases in their daily life, but this weakness can be particularly troublesome right after surgery, when men are more likely to succumb to post-op infections than women.

But, as with so many issues of men’s health, this explanation isn’t iron clad. It has also been suggested, for example, that women are just more valuable as hosts, so they’re more likely to survive infection. As a result, when men are infected, they die. But when women are infected, they survive (even though surviving also means that they’re spreading disease to their children).

Other negative effects associated with testosterone include increasing bad cholesterol, increasing the risk of heart attack and stroke.

See also: Sperm Radar Might Illuminate Male Infertility

Bad Hombres

Biology isn’t the only medical problem affecting men, however. The particular stresses of masculinity and societal pressure of what masculinity should be seem to play a critical — and negative — role in men’s health issues.

Society has made up a lot of rules about what is masculine and what is feminine. To be fair, both paradigms can kill. Women are taught to be obsessively body conscious, but men are taught the opposite, to not think much about their corporeal form at all, leading to a poorer diet and smoking rates higher than women.

And because men are taught they’re stronger than women, they’ve historically been the ones sent to war, where many — sometimes even most of a generation — are killed. Relatedly, the notion that “pain is gain” and that real men can overcome anything with perseverance, means many men avoid the doctor even when something feels off. When they eventually make it to the clinic, men are less likely than women to follow through on their doctor’s orders, not helping their morbidity rates.

Perhaps most painfully, men in the United States typically often don’t have the number of social ties that women do, especially in older age. That can makes them more easily isolated. Isolation is sad on its face, but it also comes with numerous health effects, including increased likelihood of substance abuse, vulnerability to mental health issues, physical problems like heart disease, even suicide.

Exactly what to do about these gender health disparities is unclear, but taking a page from history might help. A few decades ago, activists and experts decided that the high rates of maternal and child mortality worldwide were inexcusable. A movement was born. Today, women are living longer and better lives and have more resources and doctors dedicated just to them. Men, take note.

Photos via The Godfather