Out for the count

Increased chemical use is thought to be contributing to an increase in male infertility as sperm counts fall worldwide.

- NICKY PELLEGRINO

Evidence is mounting that male reproductive health is on the decline and an international group of experts has called for urgent action. Their report highlights the need for greater understanding of the causes of male infertility and how to better diagnose, treat and prevent it.

Lead author Moira O'Bryan, dean of science at the University of Melbourne, says compelling data shows human sperm counts and quality are dropping. One recent review found that sperm counts have fallen by more than 50% in the past 50 years.

It's believed that increased use of endocrine-disrupting chemicals is playing a role. These chemicals, which mimic, block or otherwise interfere with hormones in our bodies, are found in everything from pesticides and household chemicals to cosmetics and have been linked to a range of health problems.

A number of animal studies have associated exposure to endocrine-disrupting chemicals with a decline in sperm quality and quantity, as well as increased DNA damage in sperm. With humans, it is more difficult to draw a conclusion about how great a contribution these chemicals are making to male infertility.

"It is complicated as there are other factors," says O'Bryan. "We know, for example, that some medications dampen down fertility. Humans also smoke, drink alcohol and wait until they're 45 to try to have children. There are probably genetic factors as well."

The World Health Organisation estimates that infertility now affects one in six couples of reproductive age. About half the time it originates from the male.