A man's chances of fathering a boy or a girl are written in his genes, research suggests.
Analysis of more than 900 family trees dating back to 1600 has suggested the existence of a ' fatherhood gene' that determines the sex of a man's children.
As men inherit the gene from their parents, males who have lots of brothers are likely to have sons and those with many sisters have high odds of fathering daughters.
Corry Gellatly, a research scientist at Newcastle University, analysed the histories of 927 European and American families, comprising more than 500,000 people.
The results suggested that a gene controls whether a man's sperm contains more X or Y chromosomes, which in turn determine the sex of his children.
A child's sex is determined by the father because a woman's eggs only contain X chromosomes. When one of these combines with a sperm carrying an X chromosome, a girl is created. If it combines with a Y, the result is a boy.
It is thought that the gene comes in three forms. Men that inherit the first produce more Y sperm and have more sons. Those with the second-type produce equal numbers of X and Y sperm and so are as likely to have a boy as a girl.
The third form skews the tendency towards daughters, the journal Evolutionary Biology reports.
Mr Gellatly said the simple system would help keep the number of boys and girls born roughly equal.
He said: 'If there are too many males in the population, for example, females will more easily find a mate, so men who have more daughters will pass on more of their genes, causing more females to be born in later generations.' continues here
Analysis of more than 900 family trees dating back to 1600 has suggested the existence of a ' fatherhood gene' that determines the sex of a man's children.
As men inherit the gene from their parents, males who have lots of brothers are likely to have sons and those with many sisters have high odds of fathering daughters.
Corry Gellatly, a research scientist at Newcastle University, analysed the histories of 927 European and American families, comprising more than 500,000 people.
The results suggested that a gene controls whether a man's sperm contains more X or Y chromosomes, which in turn determine the sex of his children.
A child's sex is determined by the father because a woman's eggs only contain X chromosomes. When one of these combines with a sperm carrying an X chromosome, a girl is created. If it combines with a Y, the result is a boy.
It is thought that the gene comes in three forms. Men that inherit the first produce more Y sperm and have more sons. Those with the second-type produce equal numbers of X and Y sperm and so are as likely to have a boy as a girl.
The third form skews the tendency towards daughters, the journal Evolutionary Biology reports.
Mr Gellatly said the simple system would help keep the number of boys and girls born roughly equal.
He said: 'If there are too many males in the population, for example, females will more easily find a mate, so men who have more daughters will pass on more of their genes, causing more females to be born in later generations.' continues here
![Churchill, Hitler and the Unnecessary War](http://patbuchananbooks.com/wp-content/uploads/bk-pjb-chuw165.jpg "Churchill_Hitler_the_Unnecessary_War\")
Post a comment on AAWR
0 Responses to "Boy or a girl? It's in your genes, dad"Post a Comment
We welcome contributions from all sides of the debate, at AAWR comment is free, AAWR may edit and/or delete your comments if abusive, threatening, illegal or libellous according to our understanding of, no emails will be published. Your comments may be published on other nationalist media sites worldwide.