A study by Newcastle University suggests a man’s genes play a role in determining the sex of a child in a mother’s womb. Men acquire the inclination to have more sons or daughters from their parents. In other words, a man with many brothers is more likely to have sons while a man with many sisters is more likely to have daughters. ”However, in women, you just can’t predict it,” the study adds.
The study involved thousands of families, helping prospective parents to understand whether they will have sons or daughters. The research involved 927 family trees containing information on 556,387 people from North America and Europe going back to 1600. The family tree revealed that the chances of having a boy or a girl are inherited.
Men ascertain the sex of a baby depends on whether their sperm is carrying an X or Y chromosome. An X chromosome combines with the mother’s X chromosome to make a girl (XX) and a Y chromosome combines with the mother’s to make a boy (XY). The study suggests that an ‘as-yet-undiscovered gene controls whether a man’s sperm contains more X or more Y chromosomes, which determines the sex of his children.
To Know More, You May Refer To:
Gellatly et al. Trends in Population Sex Ratios May be Explained by Changes in the Frequencies of Polymorphic Alleles of a Sex Ratio Gene. Evolutionary Biology, Dec 11, 2008; DOI: 10.1007/s11692-008-9046-3