British scientists have created human sperm using embryonic stem cells for the first time, which they say will lead to a better understanding of the causes of infertility.

Researchers from Newcastle University and Northeast England Stem Cell Institute say the technique they have developed proves sperm can be made in the laboratory. Their work, led by professor Karim Nayeria from Newcastle University, was published in the journal Stem Cells and Development.

Nayeria said he and his colleagues' research could help couples wanting to have children, and it could lead to a better understanding of how toxins affect reproduction. For example, he said he will look into why young boys who undergo chemotherapy can become infertile for life.

Nayeria also said his research could lead to a better understanding of how genetic diseases are passed on.

The sperm was created from stem cells taken from s five-day old male embryo.