Looking for Mr. Right to start a big family with? Science says you should start by counting how many brothers he has.
Scientists say that the more brothers a man has, the greater his baby-making potential, after discovering a link between the swimming speed of a man’s sperm with the number of male siblings in his family.
The latest findings, published in the Asian Journal of Andrology, add to a previous theory that parents with genes for good male fertility are more likely to have boys. If the theory is correct, it seems Americans have excellent male fertility genes. According to the latest report from the U.S. Centers for Disease Control and Prevention, more boys than girls are being born in the United States, and there were exactly 94,232 more male births than female births in the U.S. in 2004.
Researchers at the University of Sheffield compared the traveling speed of 500 men with their family make-up.
The study found that the greater number of brothers rather than sisters a man has, the faster his sperm, and faster sperm is associated with greater fertility. Researchers noted that having mostly brothers can also indicate that the man’s parents have strong male fertility genes and that they could have passed it on to him.
“The results are very surprising and could provide genetic insights into why some men are more fertile than others but at the moment have no clinical relevance to how we might manage and treat male infertility,” researcher Dr. Allan Pacey, of the University of Sheffield, said in a statement. Read full article.
