Pregnant women exposed to everyday items may find their son's fertility and that of future generations has been harmed, a study has suggested.
A report published by the Endocrine Society found that male mice prenatally exposed to a chemical routinely found in consumer products had less testosterone and fewer sperm than mice that were not, with their male offspring suffering similar abnormalities.
Researchers from the University of Illinois studied the effect of di-(2-ethylhexyl) phthalate (DEHP), a plasticiser which disrupts the body's hormone system.
It is found in a wide array of industrial and consumer products, including cosmetics, plastic toys, medical devices and PVC piping and tubing.
Lead author Radwa Barakat said: "Most surprisingly, the male mice born to male mice that were exposed to DEHP also exhibited similar reproductive abnormalities, indicating prenatal exposure to DEHP can affect the fertility and reproductive capacity of more than one generation of offspring.
"Therefore, DEHP may be a contributing factor to the decreased sperm counts and qualities in modern men compared to previous generations."
Researchers in the study gave pregnant mice one of four doses of DEHP from 11 days after they conceived until they gave birth.
Adult males born to these mice were bred with female mice who had not been exposed to the chemical to produce a second generation. A third generation was bred in the same way.
When each generation of mice was 15 months old, their sex hormone levels, sperm concentrations and movement were tested.
In the second generation of mice, only those whose fathers had been subject to the highest exposure level of DEHP exhibited abnormal reproductive results.
But in the third generation even those descended from mice who received a lower dose showed impaired fertility.
Mr Barakat added: "This study underscores the importance of educating the public to try their best to reduce their exposure to this chemical and also the need to substitute this chemical with a safer one."