Exposure to pesticides and solvents can further lower fertility among infertile men, a new report suggests.The study shows these chemicals may worsen the effect of pre-existing genetic or medical risk factors for infertility.
The authors stress the findings should be treated with caution because they involved a selected population of infertile men, from a productive farming region in Austria. But they say the dramatic nature of the observed changes in semen quality warrant further attention.
Among men seeking infertility treatment, those who were exposed to pesticides were most likely to have a very low sperm output - in the bottom 25 per cent of the male population.
What's more, sperm concentration, output and morphology were all significantly worse in men who were more frequently exposed to the chemicals. Changes in the level of reproductive hormones in the blood were also seen.
"Our results suggests toxicants act on the testes and post-testicular sites, including the accessory sex glands," said study author Dr Luc Multigner, from France's Institut National de la Santé et de la Recherche Médicale. The findings are released today in the journal Human Reproduction.
Environmental hazards to male reproductive function were first revealed 30 years ago, when the process of sperm formation was shown to be severely impaired among pesticide manufacturers and agricultural workers.