If you want a big family, then you might be in luck if you choose a partner who has lots of brothers!
The greater the number of male siblings your partner has, the more fertile he is likely to be, scientists claim.
Researchers have discovered that men with mostly brothers are likely to be more productive and more fertile, reports The Daily Mail.
Experts from the University of Sheffield assessed 500 men and compared the travelling speed of their sperm with their family make-up.
“We found the greater number of brothers, rather than sisters, a man has the faster his sperm is, increasing the likelihood of fertility,”says Dr Allan Pacey, one of the researchers from the University of Sheffield.
“Lots of brothers is also an indication that the man’s parents have strong male fertility genes, and they would then be passed on to the son,”says Dr Allan.
“The results are very surprising and could provide genetic insights into why some men are more fertile than others.”
Researchers also stressed that the findings did not mean that men with a large number of sisters should worry, and they didn’t look at whether women with lots of sisters are likely to be more fertile, as it is much more difficult to measure.
Want to share your experiences of trying for a baby with other mums? Head to the MFM forum now