1/4 men worldwide have difficulty in having children

A study conducted in the US, the UK and China showed that up to a quarter of men around the world have a genetic defect that could reduce their chances of having children.

Scientists have found some sperm lacks a protective protein gene that helps it to reach the egg.

The protein gene, called DEFB126, coats the sperm and allows it to penetrate mucus in the female reproductive tract. It also protects the sperm from attack by the female immune system.

Without a protective protein barrier, sperm struggles to reach its goal. It reduces 30 percent of pregnant rate of his partner.

"In 70 percent of infertile men, you can't explain their infertility on the basis of sperm count and quality. The discovery could help explain a significant proportion of male infertility worldwide," said lead researcher Professor Gary Cherr, from the University of California at Davis.

The study can also bring the new methods of screening and curing infertility. 

A test for defective DEFB126 could help fertility clinics decide whether couples should be given ICSI treatment (intracytoplasmic sperm injection).

The research is published today in the journal Science Translational Medicine.