It has been observed that in certain periods the ratio of boys to girls born changes. As a rule, it is associated with wars, famines, or natural disasters. According to scientists, nature itself acts as a population regulator.
Quality, not quantity
American demographers have found that the average ratio of boys to girls at birth is, respectively, 105:100. That is, more boys are born initially. At the same time their number decreases with age, because boys and men die more often from diseases and accidents, and the average life expectancy of men is several years shorter than that of the fairer sex.
But in emergencies the ratio of the number of newborns changes. And not in favour of boys. In hard times, fewer boys are born than girls. But they are healthier than the “unproblematic” generations, and they give birth to healthier children.
Scientists hypothesized that the reason for this is the stress that forces the mother’s body to terminate the pregnancy at the risk of having a nonviable child, in order to give her the opportunity to conceive a stronger baby. Miscarriage is not always traceable, sometimes it occurs in the early stages, when the woman does not even know that she is pregnant.
By the way, boys are more likely to die in utero than girls. This can be explained by the fact that a girl has a better chance to continue her line. Nature originally made the female body stronger to ensure childbearing. This is how the mechanism of evolution works – it is aimed at the survival of the population by “culling” the weak embryos. And, apparently, this is one of the reasons why women live longer than men on average, although their reproductive period is much shorter.
Confirmation of the hypothesis
In their study, the Americans used data collected by a lady biologist from Finland. She managed to digitize the records in the church books of five Finnish cities from 1790 to 1870. At that time, there were no contraceptive and abortion methods that could affect the statistics. Specialists identified 16 “difficult” years when boys were born significantly less than girls, but at the same time there were 12% fewer deaths in the first year of life than among those who were born in calmer times. Further tracking of the information showed that 8.7% more children were born to these male winners in the struggle for survival than to others. Thus, the hypothesis of natural selection among boys is confirmed.
The compensation mechanism
It is also an undeniable fact that the number of newborn boys always increases after a war. Most researchers believe that nature seeks to fill the “gaps”, because during the war a lot of men die at the front, therefore they will no longer become fathers, and women have less chance of conceiving. If a boy rather than a girl is born, then evolutionary compensation, restoration of population balance, occurs. Such phenomena are not uncommon in the animal world. But it has now been proven that it applies to the human species as well.
One cannot argue with the fact that both sexes play very important roles in the evolutionary process, so nature ensures humanity’s survival in this way.
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