MALE fertility could be reduced by exposure to chemicals in the environment, according to a study.

A rise in IVF treatments could be down to the effect of chemicals such as cosmetics and pollutants.

Experts at Glasgow University, collaborating with Edinburgh academics, the James Hutton Institute, the University of Aberdeen and INRA in France, think the chemicals affect a certain subset of men.

The researchers looked at the testicles of sheep that had been exposed to a range of chemicals that humans encounter in everyday life, and found abnormalities that could result in low sperm counts in the testicles of 42% of the animals.

The changes were not the same in all those affected and were not obvious from the size of the testicles or the concentration of male hormones in the blood.

The year-long experiment saw 12 sheep grazed on land that had solid human waste applied to it. Their mothers also grazed there, meaning the sheep were exposed throughout their life cycle.

The animals were then euthanised and their testicles examined. Three sheep had smaller testes than normal, with a reduction in the number of sperm-producing germ cells found in the tissue. Two other sheep's testes looked normal but also showed the same reduced germ cells.

Professor Neil Evans, from the University of Glasgow, said it was unclear why five sheep were affected and the others were not.