As per a research, where American scientists from a number of universities analyzed human exposure to phthalates, it has been found that phthalates cause harm to genitals of new born male babies. The findings are the first to support the hypothesis that prenatal phthalate exposure at environmental levels can adversely affect male reproductive development in humans. Previous studies on male animals, mainly rodents, have shown that high levels of phthalates can make them more feminine and lead to poor sperm quality and infertility. The new study indicates that exposure to normal levels of phthalates may have a similar effect on humans.

A national study in the US found that the majority of the general population had measurable exposure to multiple phthalates, as phthalates can be found in soft vinyl plastic toys, medical tubing and fluid bags and a variety of cosmetics such as perfume, lotions, shampoo, make-up, nail polish and hairspray. Researchers collected data from 85 mother-son pairs. Prenatal urine samples were analyzed for the presence and quantity of 9 phthalate metabolites. The 85 male children were then examined for genital characteristics that serve as markers of normal sexual development. The findings suggest that some phthalates have anti androgenic effects, meaning they may suppress the hormones involved in male sexual development. Higher levels of 4 phthalate metabolites (mono-ethyl phthalate [MEP], mono-n-butyl phthalate [MBP], mono-benzyl phthalate [MBzP] and mono-isobutyl phthalate [MiBP]) were found to correlate with a higher than expected number of abnormalities in genital development including smaller anogenital distance, scrotum and penis and an increased likelihood of undescended testicles. The findings were consistent with those from previous rodent studies on phthalate exposure.
These changes in humans associated with prenatal exposure to some of the same phthalate metabolites that cause such alterations in male rodents suggest that these widely used phthalates may undervirilize humans as well as rodents.