Why are men stronger than women?

In starvation situations women tend to survive better than men, in part because they also tend to carry more bodyfat. Look at the statitistics for the Donner Party - most of the women survived, most of the men died.

NASA and Air Force research indicates that women cope with high g forces better than men.

A greater number of women live to extreme old age than do men.

Women who suffer from a stroke are less likely to completely lose a function such as the ability to speak. If they do lose such an ability, they are more likely to recover it during rehabilitation.

But, to go back to your original slip of the tongue - I’m not sure how you’d define the question to compare the stress men endure with the stress women endure, but I’m curious that you would “strongly disagree” with a claim that women have more stress than men. I could see a possible debate from it, but the kneejerk “I disagree” is a little interesting.

Anyhow, in the sense of brute strength, men are, on average, unquestionably stronger. Why? Well, there is a biological division of labor in the human species whether we like it or not. Women bear and nurse children. Given our long gestation and infancy, human children survive better when the father (and other relatives) become involved in their upbringing. Men’s role in all this is to protect the women and children from physical threat, protect them from other human males (bride theft and murder being a feature of some pre-modern societies), and acquire high-protein sources of food (that is, hunt or fish). As a general rule, brute strength improves the ability of men to fulfill these roles.

Biology, however, involves trade-offs. If you tweak one system it will affect others. The biological and emotional factors that make men effective guardians and hunters also make them more likely to get into accidents, fights, or suffer from heart disease. Their joints tend to be less flexible, which provides better support when using their strength, but, well, makes them less flexible overall. Men devote more of their calories towards building and maintaining muscle at the expense of their bodyfat, which makes them more suspectible to famine. (Not a huge issue in the modern West, but for most of our history famine was a greater danger than obesity)

On the flip side, because women don’t require joints that can support heavier muscles they do tend to be more flexible throughout life. Their immune systems are more fine-tuned than those of men, since they must carry a child for nine months, a child that is genetically only half theirs and should be soundly rejected as foreign tissue by their bodies (this “fine-tuning” may also may them more suspectible to auto-immune diseases). As pointed out, their greater bodyfat tides them over lean times. Their smaller body size and caloric requirements would also make them more famine resistant. Women are less inclined towards risk-taking and agressive behavior (although they are capable of both) which keeps their accident rate down - which is important since, most of the time, they are the primary child-care givers and need to live long enough to see their children to adulthood.

None of which makes for a good argument for keeping women barefoot and pregnant, and men working 12 hours a day outside the home. Human men are universally involved in raising children, and, past weaning, are just as capable of raising children to adulthood as women (in modern societies with baby formula available, they are just as capable of taking care of newborns as well). Likewise, when a “breadwinner” male is absent from the family unit, women are quite capable of working outside the home. Humans are not biologically locked into gender roles the same way ants and bees are locked into theirs. Behavioral flexibility is as much a human characteristic as our opposable thumb.

The current physical forms of human men and women were the ones that maximized the survival of offspring during most of our existance as a species. That’s why men are stronger - strong men tended to have more survivng children.