7 Surprising Causes of Male Infertility

Most men don’t think much about their reproductive health until they’re actually ready to have children. When they do they are a little older, with the average father today being 31, up from 27 in 1972. The male is responsible for a couple’s infertility in 4 out of 10 couples, however, there are many causes of male infertility, including some that are better to address before it’s baby-making time.

As co-director of Lahey Hospital & Medical Center’s Center for Sexual and Reproductive Health in Burlington, Massachusetts, urologist Andrew R. McCullough, MD, often counsels male patients and couples struggling to get pregnant. “Many of the factors that contribute to infertility in men are reversible,” Dr. McCullough said. “Anatomical or genetic causes are not always preventable, but many can be treated or overcome.”

What are the common causes of male infertility? And how can men improve their reproductive health, whether they’re trying to start a family now or just want kids in the future?

1. Obesity

Dr. McCullough says that people often fail to realize how much obesity can affect the male hormones necessary for reproduction.

“The feedback between the brain and the testes is dependent on estrogen,” Dr. McCullough said. “Estrogen is made in the fat cells, so obesity increases men’s estradiol level, which causes a reflex decrease in their testosterone level. I recently saw a 34 year old obese man whose testosterone was so low that he had no sperm. Low testosterone is not just an ‘old man’s’ problem. Studies have clearly shown that weight loss can actually increase a man’s testosterone.”

2. Male-Pattern Baldness Medications

Men with the genes for male-pattern baldness often begin taking medication to help prevent balding in their 20s and early 30s, not realizing that these meds can affect their sperm quality. The drug Propecia™ has been found to contribute to erectile dysfunction, decreased ejaculate volume, decreased libido, and decreased sperm counts. Luckily many of the effects are reversed after the medication is stopped.

“They start on this medication before they enter into a relationship, and they continue to take it, not realizing that it can affect their sperm count and ejaculate volume,” Dr. McCullough said. “It’s something they don’t think about at the time. They’ve been on it since they were 25, and they don’t associate the medication they’re taking for their hair with fertility issues.”

3. Performance-Enhancing Drugs

Anabolic steroids, found in both illegal drugs and some over-the-counter products, can have significant and sometimes lasting effects on male fertility.

“It’s not just pro sports players who use performance-enhancing drugs,” Dr. McCullough said. “One in 10 high school athletes will take some kind of performance-enhancing drug and in the competitive ‘high stakes’ world of college sports, the number is even higher. As men age they may also take over-the-counter sexual enhancers. The over-the-counter drug industry is very poorly regulated. The concentration of the advertised drugs on the label may be incorrect, the product may contain pharmaceutically active ingredients that are not reported or there may be impurities from the unregulated processing. A seemingly harmless nondisclosed additive, such as DHEA, to a protein powder can shut down the man’s own production of testosterone. I see it in patients’ lab work.”

4. Marijuana and Alcohol

Marijuana and alcohol don’t just slow down the brain — they also slow down sperm.

“Marijuana can affect the brain-testis interaction and has been shown, experimentally, to depress sperm function,” Dr. McCullough said. “Excessive alcohol is toxic to many things in our bodies, so binge drinking or heavy drinking can negatively impact fertility. There’s arguable data about the effects of smoking, but my intuition is that it can’t be real healthy for the sperm.”

5. Varicose Veins on the Testes

Men have long been cautioned against wearing briefs or getting in hot tubs when trying to make a baby, but Dr. McCullough says that those warnings are mostly old wives’ tales.

“If you’re in the hot tub for hours every night, you’re going to overheat your testicles, but underwear type probably isn’t going to do it,” he said.

What’s more important, he adds, is to make sure that men are evaluated for varicoceles, enlargements of the veins within the scrotum that are essentially varicose veins around the testes.

“In men with varicoceles, the testes stay one degree higher, which can negatively impact sperm production and function,” Dr. McCullough said. “One degree might not seem like a lot, but it’s continuous, and our enzyme systems are finely tuned to work differently at certain levels. The good news is that this condition is treatable and correctable.”

6. Absence of the Vas Deferens

The vas deferens is the duct that conveys sperm from the testes to the urethra. During a vasectomy, urologists cut or block the vas deferens to prevent pregnancy. But some men are born without one.

“With congenital absence of the vas deferens, the plumbing is defective, so he’s producing sperm, but they’re not coming out,” Dr. McCullough said. “It’s not reversible, but it’s treatable. We can go in there and retrieve the sperm.”

7. Genetics

While most causes of male infertility are reversible or treatable, genetic causes usually aren’t.

“Some men don’t produce sperm or produce very low levels of sperm, usually due to some chromosomal abnormalities that make them sterile. In 50 percent of cases, sperm can be found when the testes are biopsied and used in an invitro fertilization procedure,” Dr. McCullough said. “In the absence of genetic issues, the best way to improve male fertility is to live healthier, stop [using] marijuana, lose weight, stop drinking and smoking, and stop taking male-pattern baldness medications. People have to own up to their reproductive health, especially the factors that affect their overall health. It’s not just about making a baby. It’s also about being alive to raise the child.”

If you’re concerned about your fertility, visit the Center for Sexual Function to speak with a specialist.


*The content on this website is for informational purposes only and is not medical advice. Please consult a physician regarding your specific medical condition, diagnosis and/or treatment.

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