A study published last week says boys who were exposed to high levels of a chemical found in plastic products in the womb are being born with genital problems, including smaller penises. The study, titled Prenatal Phthalate Exposures and Anogenital Distance in Swedish Boys, focused on a compound called diisononyl phthalate (DINP), which was recently adopted as a substitute for another shunned chemical called diethylhexyl phthalate. However, apparently DINP is just as bad as what it's replacing.
"Replacement products should be tested before being put on the market," Shanna Swan, one of the authors of the paper, told me. Swan works at Mount Sinai School of Medicine's department of preventive medicine, where she studies the effects of endocrine disrupting chemicals, or "chemicals that our bodies can confuse with its own hormones." She and the other authors have been performing a form of ex post facto safety research for the companies that manufacture these chemicals, which are mainly used to harden vinyl products into the material we typically call plastic.
"We found that boys exposed to higher levels of this phthalate DINP--like the phthalate it is replacing, DEHP--had genital tract changes, in the direction of being somewhat less masculinized," she told me, paraphrasing the paper. The numbers were gathered by measuring the the anogenital distance (AGD) of newborns, or the distance between the anus and the genitals, which she told me "was shorter when DINP levels were higher in the moms' urine." While it may be mildly hilarious to talk in such serious tones about--let's face it--baby taints, the AGT keeps showing up in news stories about plastics as a sort of canary in the endocrine coal mine.
And altered baby genitals aren't the only danger. The World Health Organization issued a warning in 2012 about these chemicals, saying that children who are exposed to them in the womb may be at increased risk for "endocrine-related cancers, behavioral and learning problems, including ADHD, infections, asthma, and perhaps obesity and diabetes," in addition to hormone problems. In 2013, Nicholas Kristof of the New York Times compared these sorts of plastic additives to what lead was in the middle of the 20th century: a quiet health menace that hasn't yet received the bad publicity it deserves.
A more famous chemical of this type, Bisophenol-A (BPA), was only recently banned by the FDA as an additive in baby bottles and formula containers, even though a study in 2007 had sounded the alarm. "BPA-free" started being printed on ostensibly safe plastic bottles from companies like Nalgene soon after. However, recent studies have found that the new boss, BPS, may be the same as the old boss--just as (sorry for all the acronyms) DINP has turned out to produce similar signs of endocrine disruption as its predecessor DEHP.
So in amounts that can very easily occur from normal exposure to these products, you can have your hormones altered enough that if you're pregnant with a boy, it can definitely shrink your baby's grundle, and possibly his dick.
"Boys with genital birth defects (like hypospadias and undescended testicles) and adults with infertility or low sperm count have shorter AGD. Even small differences may make a significant change in the man's fertility," Swan told me.
Further hammering home the point about possible changes in penis size, she told me that "this study just looked at AGD. In connection to DHEP exposure we saw smaller penile size, [and] less completely descended testicles." The connection between multiple measurements isn't conclusive, she hastens to add. "We need to study these endpoints in relation to DINP as well."
So, in other words, it's too early to say that plastic bottles can definitely shrink baby dicks, but there is certainly cause for concern.
Follow Mike Pearl on Twitter.