Sperm counts have dropped by almost third in 10 years

LONDON (AFP) - Male sperm counts have fallen by almost a third since 1989, with factors such as drinking and obesity possibly to blame, according to a British study.

A survey of 7,500 men who attended the Aberdeen Fertility Centre in northern Scotland between 1989 and 2002 brought alarming findings, researchers said Monday.

Analysis of sperm samples showed that in men with what is considered a "normal" concentration of sperm -- defined as over 20 million sperm per millilitre of semen -- the average sperm count fell by 29 percent.

This "must cause some concern and needs to be explained", said Dr Siladitya Bhattacharya, who led the research project.

"There could be a number of lifestyle factors which could play a role in this," he said.

"It just highlights the need for research to discover what these reasons might be, as well as the need for further studies elsewhere in the country to see if they support our results."

Drug use, alcohol, smoking and obesity have all been linked to a decline in sperm counts, as well as pesticides and other chemicals in the environment.

In 1986, Scotland was affected by the fallout from the Chernobyl nuclear disaster, but Bhattacharya said it was "almost impossible" to say for certain whether this or any other individual factor was to blame.

It could also not be concluded that there had been a fall in male fertility, as factors other than just sperm count played a part, he added.

"There has been an increase in men seeking treatment for male infertility, but whether this is due to a significant increase in this condition or because men are more aware of new techniques which have been developed to help them, we cannot say."