I seem to remember that about 52% of the world’s population is female, as opposed to an actual 50/50 split. Is this true? if so, what is the exact number? And most importantly, what causes it?
No idea about the exact numbers, but I’d guess that the discrepancy is due to the fact that women have a slightly higher average life expectancy than men do.
Johnny Bravo is correct. In fact, more male babies are born than female, but the difference in life expectancy more than makes up for the head start that we XY types get.
Wow, people reply so fast on this board! Thanks for the help, you two. (By the time I push “Submit,” it might be more.) I hadn’t thought about the life expectancy issue, but it seems rather obvious now. Thanks again!
Perhaps an even more interesting question is why the sexes ratios are so close? Do most species have such a similar male to female ratio? Because one man can impregnate many women, it seems to make sense that fewer males are needed than females, who are much more limited in the number they may have.
This old thread pretty well hammers with sex ratio question into the ground.
IIRC, 40% more boys are conceived than girls, but do not very well in gestation.
More boys than girls are delivered on this globe…The reason I was taught and read was that women are generally healthier…survive surgeries better than men age group for age group and see doctors more frequently for general checkup. Thusly, life requires more males born than women to even the playing field.
A 40% difference? I would be shocked if the ratio at conception were so far from 1:1. Where does that number come from?
I had read something similar, although I couldn’t give you a site.
Anyway, a large proportion of male embryos miscarry (most of them VERY early on so the mother may not even know she’s pregnant), probably because the XY congifuration makes them more susceptible to fatal genetic defects.
At birth, there are 1.05males born for every woman. In the the United States, that ratio drops to 1:1 in the 15-64 age group. In the 64+ age group, there are .71 males per females. The average U.S. population is much closer than you would think, being .97 males per female.
That doesn’t hold true throughout the world, though. In 3rd world nations where childbirth-related illness take a heavy toll, thre is a lot of foreign worker migration, and cultural norms favor male children (leading to the abandonment or abortion of females) there are MORE males. In Saudi Arabia, for example, there are 1.36 males per 1 female in the 15-64 group. For the entire world, there are actually 1.01 males per females.
All info comes from: http://www.cia.gov/cia/publications/factbook/geos/xx.html
So why, in the western world anyway, are there more women in the upper age tier than men? Someone mentioned life expectancy earlier, and that’s half of the answer, although it does not seem that women are particularly pre-disposed to living longer. Whether predisposed by nature or culture, we men seem predisposed to take stupid risks. The vast majority of deaths from homicides, accidents, and suicides are men, which tends to eat away the numbers who make it to old age. Things like heart disease play a role, too, but once you control for non-natural deaths, the numbers of men and women get a lot closer.
Also, we can’t forget about the lingering affects of WWII. Although the U.S. got off pretty lightly, many nations lost over 10% of their populations, mostly their men. In Russia, for example, there are TWICE as many women as men in the over 64 group, and Germany and Japan are almost in the same boat.
As recently as the late nineteenth century, the life expectancy of females was no longer than that of males. Now in most countries females live longer on average, often by as much as six years. The difference is that women no longer die in childbirth (or hardly ever do) in any country with even reasonable amounts of modern health care.