Rubber ducky, you’re gonna have to be the one!

A new study links phthalates to lower estrogen and testosterone in men, hormones which are necessary for sperm. It’s the first study to show a relationship between the plasticizer and hormones in adult men.

Animal studies have long suggested a relationship between phthalates and sex hormones.  Phthalates are endocrine disruptors, which means they have been shown to interfere with hormones and the processes that they control, such as puberty.  They’ve been linked to fabulous things like cancer and in boys, a genital deformity called hypospadias, where the urinary opening is misplaced on the shaft of the penis. They’ve even been linked to a smaller androgenital distance: that’s a nice way of saying the penis is shorter. Honey, we shrank his penis.

Congress passed a law last year to make toys safer, which included removing phthalates from children’s gear.  I will point out that manufacturers have until February 10 to comply, so these products may still be on shelves.  And be extra wary of anything at your local Dollar Store. Even with the new law, phthalates are found everywhere, from your beauty products and your shower curtain to air fresheners and medical devices.

In this study, researchers took samples from 425 men who seeked help for fertility.  Exposure to phthalates is apparently one of the factors discussed when couples seek treatment. (Though I wouldn’t know, as Mark and I got pregnant by sneezing next to one another.)  Researchers then measured breakdown products of DEHP (di(2-ethylhexyl) phthalate, of course!) and other phthalates in urine and compared those levels to hormone concentrations measured in the blood of the men.

The more DEHP metabolites they measured in the men, the lower the levels of estrogen they found. The DEHP metabolites were also linked to lower testosterone.  They interfered with the hormone linking to a specific protein, which whisks them away to where they’re needed.

Less testosterone traveling in the blood may result in lower hormone levels in key cells that guide reproductive processes, leading to reduced maleness.

Study authors warn this isn’t a conclusive study…yet.  Other factors may account for the “reduced maleness”, though they did take in to account age, BMI, smoking status, season of the year and the time of day that the blood samples were collected, and the subjects’ horoscopes.

The study was published this week in Environmental Health News.

Image: Annie Ominous on Flickr under a Creative Commons License.