Dr. Marianne J. Legato — Gender Medicine Expert and UpSpringMedical Advisor — recently shared with BuzzFeed Parents some surprising facts about male infertility you probably did not know.
1. Retrograde ejaculation — where semen goes into the bladder instead of out of the penis — is a very real thing.
Diabetes and some medications can cause this condition, which, as you can imagine, affects a man’s fertility.
2. A loss of smell can be a sign of infertility.
Loss of smell is associated with Kallmann syndrome — a genetic disorder that prevents a person from starting or fully completing puberty. If left untreated most people become infertile.
3. Overweight men tend to have lower testosterone levels, poor sperm quality, and reduced fertility.
Also, the more overweight a man is, the more it affects his fertility. For every 20 pounds overweight a man is, it increases his odds of infertility by 10%.
4. Depression or emotional stress can impair a man’s fertility.
5. Men who chew betel nuts — which are popular in Taiwan and other parts of Asia — tend to have offspring with a significant number of developmental disabilities.
6. A loss of facial or body hair can also be a sign of conditions that impair fertility.
7. Love to spend a long time in the hot tub? It can impair fertility because overheating the scrotum inhibits sperm production and quality.
8. Your fertility can be affected by the lifestyle of your grandparents.
For example, one Swedish study found that a paternal grandfather who’d overeaten during the slow growth period that precedes puberty had an impact on his grandson’s health.
9. You probably had an idea that smoking wasn’t great for fertility. But did you know that even second-hand smoke exposure can reduce fertility? It’s true.
Excessive alcohol consumption is also bad for a man’s fertility.
10. Making sure you get enough Vitamin E can increase fertility.
Over 75% of men don’t meet the recommended requirement of Vitamin E, which — along with Vitamin C, zinc, folic acid, and lycopene — mitigate damage to sperm.
11. The most common reversible cause of infertility? A varicocele, which is a swelling of veins that supply the testis. It can be surgically treated.
12. Having athlete’s foot could potentially impair your fertility. That’s because antifungal drugs can be associated with lower production of sperm.
13. Some factors that impair fertility only impact the offspring of one sex. For example, men who smoked at a very early age (like before age 11) see adverse affects in their sons, but not their daughters.
14. Normally, antibodies fight things like bacteria and viruses, but there are some antibodies that actually attack sperm.
Anti-sperm antibodies aren’t common, but exist. Infections in the prostate, or an injury to the testicles, can cause them.

Marianne J. Legato, MD, Ph. D. (hon. c.), FACP is an internationally renowned academic, physician, author, lecturer, and pioneer in the field of gender-specific medicine. She is a Professor Emerita of Clinical Medicine at Columbia University College of Physicians & Surgeons and an Adjunct Professor of Medicine at Johns Hopkins Medical School. Dr. Legato is also the Director of the Foundation for Gender-Specific Medicine, which she founded in 2006 as a continuation of her work with The Partnership for Gender-Specific Medicine at Columbia University. She received an honorary PhD from the University of Panama in 2015 for her work on the differences between men and women.
At its core, gender-specific medicine is the science of how normal human biology differs between men and women and how the diagnosis and treatment of disease differs as a function of gender. Dr. Legato’s discoveries and those of her colleagues have led to a personalization of medicine that assists doctors worldwide in understanding the difference in normal function of men and women and in their sex-specific experiences of the same diseases.
She began her work in gender-specific medicine by authoring the first book on women and heart disease, The Female Heart: The Truth About Women and Coronary Artery Disease, which won the Blakeslee Award of the American Heart Association in 1992. Because of this research, the cardiovascular community began to include women in clinical trials affirming the fact that the risk factors, symptoms, and treatment of the same disease can be significantly different between the sexes. Convinced that the sex-specific differences in coronary artery disease were not unique, Dr. Legato began a wide-ranging survey of all medical specialties and in 2004, published the first textbook on gender-specific medicine, The Principles of Gender-Specific Medicine. The second edition appeared in 2010 and the third edition, dedicated to explaining how gender impacts biomedical investigation in the genomic era, won the PROSE Award in Clinical Medicine from the Association of American Publishers in 2018. A fourth edition is forthcoming.
She also founded the first scientific journals publishing new studies in the field, The Journal of Gender-Specific Medicine, and a newer version, Gender Medicine, both listed in the Index Medicus of the National Library of Medicine. She has founded a third peer-reviewed, open access journal, Gender and the Genome, which focuses on the impact of biological sex on technology and its effects on human life.
Dr. Legato is the author of multiple works, including: What Women Need to Know (Simon & Schuster, 1997), Eve’s Rib (Harmony Books, 2002), Why Men Never Remember and Women Never Forget (Rodale, 2005), Why Men Die First (Palgrave, 2008), The International Society for Gender Medicine: History and Highlights (Academic Press, 2017), and most recently, The Plasticity of Sex (Academic Press, 2020). Her books have been translated into 28 languages to date.
As an internationally respected authority on gender medicine, Dr. Legato has chaired symposia and made keynote addresses to world congresses in gender-specific medicine in Berlin, Israel, Italy, Japan, Panama, South Korea, Stockholm, and Vienna. In collaboration with the Menarini Foundation, she is co-chairing a symposium on epigenetics, Sex, Gender and Epigenetics: From Molecule to Bedside, to be held in Spring 2021 in Italy. She maintains one of the only gender-specific private practice in New York City, and she has earned recognition as one of the “Top Doctors in New York.”