The paragraph under subheading “Sex ratio without war” doesn’t sound right, it seems to imply more men are born as a result of higher mortality rate but doesn’t really make sense, how can mortality rate influence sex ratio at birth? In the general population sure. Or it’s just poorly written and is referring to sex ratio in the population in an article about birth rates.
Yeah it doesn’t seem to follow that men dying earlier/more often should be causally related to a higher male birth ratio. There is no fundamental reason the sex ratio needs to be balanced. In fact it’s pretty odd that it is; in an alternate universe where females outnumbered males 2:1, you could easily tell an evolutionary just-so story around group selection and optimal resource usage.
I think that there is a statistic reason hidden somewhere deep but would be on long scale.
Before modern science, you needed a man and a woman to make a baby.
Maybe it is for monogamous societies or would apply also to polygamy but there should be just a common average of the number of child a father will procreate. Especially taking care of the fact that he needs to be able to take care of them.
Removing outliers, must men will not do more than 1 to 4 kids for example.
So somehow if you have a too high ratio of women, birthrate will decrease, and same too many men not enough mother do birthrate would decrease also.
So there should be a natural regulation at big scale to keep the population stable or growing.
And probably, the individuals contributing to birth with the good ratio would be the one reproducing themselves so helping correcting anomalies in the long run.
There are probably also environnemental and genetic factors that are at play to determine baby gender, not only perfect randomness, that are still unknown to us.
I think a lot of people are wondering, if I have 2 kids, 2 boys, what are the odds to have a girl the third time? Is it really 1/2 or in a more cases it will be a boy again?
The graph makes it pretty obvious that the effects isn't real. The newy steady growth in ratio 1910-1950 is more interest, but even so, the magnitude of variations is tiny.
If anything, infanticide is likely the cause of distortion. Look at China's One Child Policy.
The paragraph under subheading “Sex ratio without war” doesn’t sound right, it seems to imply more men are born as a result of higher mortality rate but doesn’t really make sense, how can mortality rate influence sex ratio at birth? In the general population sure. Or it’s just poorly written and is referring to sex ratio in the population in an article about birth rates.
Yeah it doesn’t seem to follow that men dying earlier/more often should be causally related to a higher male birth ratio. There is no fundamental reason the sex ratio needs to be balanced. In fact it’s pretty odd that it is; in an alternate universe where females outnumbered males 2:1, you could easily tell an evolutionary just-so story around group selection and optimal resource usage.
I think that there is a statistic reason hidden somewhere deep but would be on long scale.
Before modern science, you needed a man and a woman to make a baby. Maybe it is for monogamous societies or would apply also to polygamy but there should be just a common average of the number of child a father will procreate. Especially taking care of the fact that he needs to be able to take care of them.
Removing outliers, must men will not do more than 1 to 4 kids for example.
So somehow if you have a too high ratio of women, birthrate will decrease, and same too many men not enough mother do birthrate would decrease also.
So there should be a natural regulation at big scale to keep the population stable or growing.
And probably, the individuals contributing to birth with the good ratio would be the one reproducing themselves so helping correcting anomalies in the long run.
There are probably also environnemental and genetic factors that are at play to determine baby gender, not only perfect randomness, that are still unknown to us.
I think a lot of people are wondering, if I have 2 kids, 2 boys, what are the odds to have a girl the third time? Is it really 1/2 or in a more cases it will be a boy again?
The graph makes it pretty obvious that the effects isn't real. The newy steady growth in ratio 1910-1950 is more interest, but even so, the magnitude of variations is tiny.
If anything, infanticide is likely the cause of distortion. Look at China's One Child Policy.
"The returning soldier effect is an observed phenomenon where more boys are born relative to the number of girls after periods of war."