The study suggests that the parabens in cosmetics and soaps lower testosterone levels and more sperm that are abnormally shaped and slow moving. Further, this may contribute to causing infertility in men.

Around 315 male patients of a fertility clinic in Poland examined lab tests by researchers. A lab test to pinpoint issues they were having with reproduction. Urine, saliva, blood, and semen of all 315 men were analyzed.

The study found that men with low paraben concentration in urine have a lower risk. Whereas men with higher paraben concentration in their urine may contribute to infertility. Since they had larger proportion of sperm with the abnormal morphology (shape and slow moving)

A high concentration level of paraben in urine is also linked to DNA damage in the sperm and with decreased sperm motility.

Joanna Jurewicz of the Nofer Institute of Occupational Medicine in Lodz said, "We have observed an impact of parabens on semen quality."

Jurewicz said it is very difficult to avoid parabens, as they are widespread. However, by using personal care products one can minimize the exposure. Personal care products with label information there are no parabens in the particular product are helpful.

Cosmetics, including soaps, creams, and makeup products widely use paraben as a preservative. Methylparaben, Propylparaben, and butylparaben are the most common parabens used in cosmetics. To increase their effectiveness, several parabens are used in combinations.

The European Union banned some parabens from cosmetics. However, the U.S. Food and Drug Administration not the limited use of the ingredients. Parabens can mimic the hormone estrogen, and lower testosterone levels suggested in past research on animals. The authors note in the Journal of Occupational and Environmental Medicine.

According to the U.S. National Institutes of Health, Developmental, reproductive, neurological and immune system side effects of Parabens and other so-called hormone disruptors. Also, they may found in pharmaceuticals, cosmetics, pesticides, plastics, detergents, food, toys, and flame-retardants.

Abnormal size and shape of sperm, an increase in the % of sperm, as well as reduced sperm motility is linked with a particular one chemical-butyl paraben.  Sperm with only atypical size and shape was associated with another chemical-ethyl paraben.

The men all joined the study after visiting a fertility clinic. Study limitation as lack of data on other environmental or medical factors might influence sperm quality or infertility. Except its small size. Since it is also possible, the results might not apply to other men.