Chemicals and Genes Can Cause Birth Defect in the Penis

Nicholas J. Jury, PhD and Elena Gerasimov, MA, MPH, National Center for Health Research

Hypospadias is a birth defect where the urethra is located on the underside of the penis, instead of the tip of the penis. Since the urethra carries urine and semen out of the penis, this causes problems for urinating and intercourse. The birth defect affects about five out of every 1,000 boys born in the United States having the penile defect. [1]

Several factors increase the chances of a baby being born with this defect:

  • Pregnant women over the age of 35 and who are obese [2]
  • Certain fertility treatments [3]
  • Women who take hormones [4] prior to and during pregnancy

Two recent studies have linked chemical exposure during pregnancy to boys being born with hypospadias. The first study reported that mothers who were exposed to chemicals at their workplaces or through the environment were more likely to have baby boys born with hypospadias. [5]  The researchers reported that exposure to cleaners, pesticides, cosmetics, paints, solvents, and industrial chemicals significantly increased the chances of baby boys being born with the penile defect. Pregnant women exposed to endocrine-disrupting chemicals, which are artificial substances that can act like hormones in the body, can cause problems with the fetus during development of the penis.

The second study focused more on how heredity can cause the birth defect. [6]  Certain genes may be more important in determining the penile defect than chemical exposure alone. However, that chemical exposure in addition to gene mutations could increase the chances of a boy being born with hypospadias.6

To learn more about endocrine disrupting chemicals and their effects on the body, please see our statement to the FDA.

All NCHR articles are reviewed and approved by Dr. Diana Zuckerman and other senior staff. 

  1. Paulozzi LJ, Erickson JD, Jackson RJ. Hypospadias trends in two US surveillance systems. Pediatrics 1997; 100:831–834.
  2. Carmichael SL, Shaw GM, Laurent C, Olney RS, Lammer EJ, and the National Birth Defects Prevention Study. Maternal reproductive and demographic characteristics as risk factors for hypospadias. Paediatr Perinat Epidemiol. 2007; 21: 210–218.
  3. Reefhuis J, Honein MA, Schieve LA, Correa A, Hobbs CA, Rasmussen SA, and the National Birth Defects Prevention Study. Assisted reproductive technology and major structural birth defects in the United States. Human Rep. 2009; 24:360–366.
  4. Carmichael SL, Shaw GM, Laurent C, Croughan MS, Olney RS, Lammer EJ. Maternal progestin intake and risk of hypospadias. Arch Pediatr Adolesc Med. 2005;159: 957–962.
  5. Kalfa N, Paris F, Philibert P, et al., Is Hypospadias Associated with Prenatal Exposure to Endocrine Disruptors? A French Collaborative Controlled Study of a Cohort of 300 Consecutive Children Without Genetic Defect. European Urology. 2015.
  6. Thorup J, Nordenskjold A, Hutson JM. Genetic and environmental origins of hypospadias. Current Opinion in Endocrinology, Diabetes and Obesity. 2014, 21:227-232.