aoeu wrote:Women are handicapped during pregnancy.
What? No they aren't. Are you trolling?
The statement was pretty terse, so it sounded to me, too, like it might be intended to be rude. But I think we're taking it the wrong way. (I thought maybe it meant "handicapped for life
." The idea is that pregnant women have a harder time with physical activities while pregnant, which makes sense. That's another point on which primitive societies could discriminate against a "less capable" group.
Derek wrote:I'm pretty sure females have been a slight majority of the population for most of human history. Until modern times, war was endemic, which meant that many men died relatively young in combat. Perhaps this is why there is a slight preference for male births? Or it could be the reverse, cultures are prone to violence due to too many young males? But I think I'm probably speculating too much now.
Do you have any citations for that? I strongly doubt that females have been a slight majority for most of human history.
I'm basing this on a few things:1.
The sperms are 50/50. There's 100 male sperms to 100 female sperms and that's because the sex is determined by the father and the father has one X and one Y, and when they split to go into separate sperms one gets an X, one gets a Y, that's even. By the second month of gestation, so this is still in the mother's womb, apparently a huge fraction of about one-third of the... female fetuses have died because now it's a high male ratio.
Then as time goes on the male fetuses start to die and when you end up, you get 106 at birth all over the world unless people are messing with it. There's about 106 male births to every 100 female births. This is a very, very fixed number, so for instance, in the United States in 1969 there were 105.3 males born per 100 females; 1995 30 something years later 104.9, so difference of .4. That number really does not vary except basically between 105 and 106. It's a very, very stable number.
"Global Problems of Population Growth" Open Yale Courses http://oyc.yale.edu/molecular-cellular- ... lecture-152.
[Global] Sex ratio:
at birth: 1.07 male(s)/female
under 15 years: 1.07 male(s)/female
15-64 years: 1.02 male(s)/female
65 years and over: 0.79 male(s)/female
total population: 1.01 male(s)/female (2012 est.)
Like I said, the population starts out skewed to males and winds up skewed to females as the population ages.
CIA World Factbook: World https://www.cia.gov/library/publication ... os/xx.html3.
For most of the years 1900-1970, there have been more males than females in the US. It almost certainly goes back further but I haven't found that data yet.
US Census Historical Data: 1900-1970 Series A 23-28 http://www2.census.gov/prod2/statcomp/d ... 0p1-02.pdf
What skews the population at birth even further in favor of males today is sex-selective abortion. Before that, it was sex-selective infanticide. The majority of cultures prefer sons over daughters.
In China, India, and elsewhere, son preference is so strong that with the invention of ultrasound, pregnant women began checking the sex of their fetuses and aborting females. In India in a single hospital one year, out of:
8,000 serial abortions… 7,999 were females. One was a male and that was probably a mistake… The head of the Women's Association in India says, ‘No one wants girls; if the test says a girl then the pregnant woman will have an abortion.’.... “Hispanic women in Los Angeles were surveyed. They want 2.8 sons on average and 0.1 daughters.... The total sex ratio [of China and India] hasn't changed all that much. In China we have pretty good data and traditionally where-ever one has data there has been a dearth of about 10% to 25% of girls from… the 1700s... [That is, 10 to 25% fewer girls than boys]. Back then it was [caused by] infanticide so what you're really seeing is a change of method that the society is going from an infanticide control of the sex ratio to an ultrasound and sex selective abortion control of the sex ratio.” (Wyman lecture 15). “In the seventeenth century, again this is from Jesuit missionaries to China, reporting back to Europe, they were horrified to find that in Beijing alone… several thousand babies, almost exclusively females, were thrown into the streets like refuse to be collected each morning by carriers who dumped them into huge pits outside the city.
There is a biological tendency to have slightly more sons than daughters, and that tendency is exacerbated by practices in cultures that prefer sons over daughters. They'll often abort female fetuses or, more rarely nowadays, just kill a female baby. It's such a widespread practice that it actually skews the birth ratio, even in a very large population.
The sex ratio at birth in South Korea is 1.07 male(s)/female. The sex ratio in India is 1.12 male(s)/female. In China, it's 1.13 male(s)/female.