According to Eating chicken may lead to a smaller penis:
to protect their sons’ normal development, pregnant women may be wise to avoid poultry
Is any of this true?
Women's Health magazine (might not be the best source, but not much else covered this) has an article explaining that PETA drew their own conclusion from the actual research on phthalates and penis size:
Reality Check: Chicken Consumption Isn't Linked to Penis Size The research PETA mentioned from the Study for Future Families didn't look at chicken consumption at all—it looked at how prenatal phthalate exposure affects boys reproductively in a variety of ways, one of which was penis size. It is true that, according to the Study for Future Families' research, boys born to moms with the highest levels of phthalate exposure (defined as those in the top 25th percentile) were more likely to have shorter penises than those born to moms with the lowest levels of phthalate exposure (those in the bottom 25th percentile).
Why? Phthalates may decrease the amount of testosterone a boy is exposed to in his mother's womb, hindering his reproductive development. This has been linked to a host of issues, such as a higher likelihood of undescended testicles and a smaller anogenital distance (the distance between the anus and the genitals; this measure has been associated with feminization). In rodent studies, prenatal phthalate exposure in males has also been correlated with lower sperm counts later in life and even infertility.
It's scary, yes, but here's the thing: You gain exposure to phthalates in lots of ways, such as when you use certain personal care products, when you eat out of plastic containers, and when you consume anything on the list of many, many foods that contain phthalates, says Shanna H. Swan, Ph.D., a professor in the department of preventive medicine at the Icahn School of Medicine at Mount Sinai, who conducted the research PETA cites. What's more, chicken doesn't even rank particularly high on the list of foods containing phthalates (spices are actually at the top of the list, according to one German study). "I think any link between eating buffalo wings—even by pregnant women—and the size of their son's genitals is very tenuous," says Swan.
(bold in original) Since one author of the study (Swan) qualified PETA's conclusion as tenuous... we can probably bother no further.