Boys and girls do NOT run in the family and the chances of having a child of both sexes are really random, scientists say
- It is often thought that the ratio of boys / girls in the offspring is a hereditary trait
- However, experts studying the gender of people born in Sweden found the opposite
- You are essentially just as likely to have a boy as a girl, regardless of previous generations
The tendency to have boys or girls does not occur in the family and the chances of having a child of both sexes are really random, scientists have discovered.
Researchers studied the gender of people born in Sweden in the last 90 years to determine if people are more likely to have children of a certain gender.
Their findings shake important theories about sex relationships used by biologists, who often assumed that the relationship between boys and girls in posterity was a hereditary trait.
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On the photo: in the Brady Bunch a beautiful lady with three very beautiful girls met a man with three own boys. In real life, the tendency to have boys or girls is not in the family and the chances of having a child of a certain gender are random, scientists report
The ratio between boys and girls among children – which researchers call the “gender ratio offspring” – is about one to one.
Experts explain this in terms of the so-called Fisher’s principle, which says that – in a population with an unequal ratio between men and women – individuals of the rarer sex are more valuable from a reproductive perspective.
Accordingly, the theory goes, individuals who are genetically inclined to have more offspring of the rarer sex will be more successful, so more children of the rarer sex will be born until the population ratio is equal.
Fisher’s principle, however, is based on the fact that the sex ratio of the offspring is a hereditary trait that can be passed on through the generations – but this has not been proven.
In their research, Dr. Zietsch and colleagues analyzed the entire population of people born in Sweden from 1932 to the present.
This included 3,543,243 people and their 4,753,269 children.
The team looked to see if there was a connection between the gender of the offspring of an individual and the gender of the offspring of their siblings.
The researchers discovered that the relationship between boys and girls is not a person’s inherent trait that flows through the generations. Instead, the gender of a person’s children is essentially random, although generally more male children are born
The researchers discovered that the relationship between boys and girls is not a person’s inherent trait that flows through the generations.
Instead, the gender of a person’s children is essentially arbitrary, although generally more male children are born.
‘We estimate that the heritability ratio for posterity sex was zero […]”Making Fisher’s principle and various other existing hypotheses unsustainable as frameworks for understanding the gender ratio of human offspring,” the researchers wrote.
The full findings of the study were published in the journal Proceedings of the Royal Society B: Biological Sciences.