Tall, Dark, Handsome … with Brothers

Male Factor Infertility

Freezing your eggs is only one part of the equation when ensuring future fertility and the ability to create a family later. So what's the other part? The person who provides the sperm!

Whether you are looking for the man of your dreams or doing your research to find a sperm donor, you might want to consider finding a man who has a lot of brothers. Why? Researchers from the University of Sheffield and Brown University have found a link between the swimming speed (motility) of a man's sperm and how many brothers he has!

Crazy, right? Not so much. Sperm motility is a major predictor of fertility and varies quite a bit among men. Researchers had hypothesized that parents who have genes for good male fertility traits, such as high sperm speed, would produce more sons and fewer daughters because the children inherit advantageous male fertility genes.

To investigate the theory, scientists did a study of 500 men who had semen analyses as part of infertility testing. They used computer technology to accurately measure how fast the men’s sperm swam and then correlated that information with the number of brothers or sisters each man had in his family.

Then, they analyzed the data and, surprisingly, found out that men who had mostly brothers in their families had faster sperm than men who had mostly sisters.

The results of the study were published in the Asian Journal of Andrology and support the theory that parents who have genes for good male fertility are more likely to have boys.

While the study does not offer any insight into the treatment of male fertility, the authors wrote: "This observation suggests family composition is an important factor that needs to be considered in future epidemiological and clinical studies of human fertility."

And, of course, it's just one more thing you can add to your list for your dream man or donor: Smart, funny, successful, talented, handsome and a lot of brothers ...

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