Chemical may inhibit male sex development

• A manmade ingredient of many plastics, cosmetics and other consumer products may be interfering with prenatal male sexual development, new research suggests.
• A study of 85 infant boys found a correlation between increased exposure to some forms of the chemical phthalate and smaller penis size and incomplete testicular descent.
• "This is clearly something that needs to be examined in a larger sample," said Shanna Swan, a professor at the University of Rochester School of Medicine and Dentistry who headed the study.
• A paper describing the research will appear in a future issue of Environmental Health Perspectives, a journal of the National Institute for Environmental Health Sciences.
• Rats with the syndrome suffer from genital birth defects, infertility and testicular cancer.
• The last few decades have seen a rise in the types of birth defects that would be expected from prenatal testosterone interference, including hypospadia, a defect in which the urethra does not extend to the tip of the penis, and undescended testicles.
• Testicular cancer has increased as well, although it is a different type than rats experience in phthalate syndrome.
• "The results are both groundbreaking and potentially troubling," said Russ Hauser, a professor at the Harvard School of Public Health who was not involved in the research.
• The researchers found a correlation between exposure to some forms of phthalate and a measurement called the anogenital index _ the distance between the genitals and the anus.
• A growing body of research suggests that some chemicals used in consumer products may cause public health problems by interfering with sex hormones.
• A study in the current issue of the journal Endocrinology exposed newborn mice to bisphenol-A, a chemical found in plastics and dental sealants, at doses comparable to those found in the human environment.