 Sexual selection may have also played a role in penis size. According to the best available science, three quarters of women find both penile length and girth somewhat or very important. What does that have to do with diet? Phthalates. Phthalates are chemical compounds using a wide range of consumer products, including pesticides, paints, PVC plastic. However, the contribution of dietary intake to phthalate exposure has not been well defined until now. What's the problem with phthalate exposure? Effects on sexual health and development have been observed in recent human studies. We've known phthalates affect the genital development of lab rats, but for the first time ever, human data has been published. Simple study, they measured the levels of phthalates flowing through the bodies of pregnant women, and then later measured the size and characteristics of their infant son's genitals after birth, between ages two months to three years. There was one phthalate particularly associated with a smaller penis, mono-2-ethylhexylphthalate, M-E-H-P. The researcher concludes these changes in male infants associated with prenatal exposure to some of the same phthalate metabolites that cause similar alterations in male rodents suggest that commonly used phthalates may under-viralize humans as well. So what foods should pregnant women stay away from to decrease their phthalate exposure in hopes of avoiding the phthalate-related syndrome of incomplete viralization? The urine levels of thousands of Americans all across the country were measured along with their diets to find out which food was most significantly correlated with phthalate body burden. They looked at dairy, eggs, fish, fruit, poultry, potatoes, tomatoes, vegetables in general, and red meat. The food associated with the greatest exposure to phthalates was poultry consumption. So for our example in one analysis, while total dairy consumption was significantly associated with one of the phthalate chemicals, it was the eggs and the poultry consumption, in particular there was a significant predictor of levels of MEHP, as well as total phthalates. This is consistent with what's been found measuring phthalate levels directly in foods. I guess there's some in other meat products, fish, fats, oils, and milk, but poultry was the worst. Suggesting that an increase in one ounce of poultry per day is associated with an increase in DHP metabolite levels of approximately 5.7%. A single chicken breast can be 8 ounces, and one of those metabolites is MEHP, the phthalate most closely tied to smaller penis size in infant boys. In fact, that was the most statistically significant finding in the whole study, the correlation between poultry consumption and MEHP. In addition to a smaller penis, MEHP appears to increase the odds of boys later growing breasts, 25-fold, and then decrease testosterone later in life. Now just because you have a smaller penis doesn't necessarily mean you're less masculine, as was widely reported, but there was actually a study published last year showing that the phthalates found in chicken were significantly associated with less masculine behavior in boys, such as playing less with trucks and more with dolls, for example. The chicken phthalates have also been associated with increased odds of cesarean section, diminished child intelligence, particularly in boys, attention deficit and hyperactivity disorder, ADHD symptoms, later in life with abdominal obesity, altered thyroid function, damaged sperm, and, as we learned this summer, a lower sperm count. Why is chicken so contaminated? Is chicken just leaching into the meat from the plastic wrap packaging? Probably not. The finding that egg consumption is significantly associated with levels of the penis-shrinking MEHP suggests that chickens themselves may be contaminated, and that food is not being contaminated just through packaging and processing. Maybe it's in the feed? Phthalates have been intentionally fed to chickens in the hopes of decreasing the cholesterol levels in their muscles and eggs, but it didn't work. Regardless if there's one thing pregnant women may want to avoid during pregnancy, to protect their son's normal development, it would be to avoid poultry.