It shouldn’t be surprising that alcohol and fertility don’t mix. As a young man, the more alcohol you drink, the lower your sperm count and the poorer your sperm quality are likely to be. Excessive alcohol intake is generally bad for health, particularly reproductive health.

Alcoholism is one lifestyle factor every man that is trying to father a child needs to be wary of. Several studies have shown that men who drink the most alcohol have the lowest sperm counts.

One study found that a significant effect was felt in men drinking as little as five units a week. A unit was defined as a single beer, a glass of wine or about the equivalent of a shot glass of liquor.

In the study published in The Journal BMJ Open, adjustments were made for

possible factors like diet, smoking, weight, etc., which did not explain the association. The research involved more than 1,200 Danish men undergoing a required medical examination to determine whether they were fit for military service.

The men were aged 18-28. They filled out questionnaires about their drinking, provided a semen sample and had their blood drawn.

Sperm concentration, total sperm count and percentage of normal sperm were all poorer among men having at least five drinks a week, compared to those drinking just one drink weekly. The amount of testosterone measured in the men’s blood, however, increased as their alcohol intake increased.

From the study, it was discovered that the drop in sperm count and quality became particularly significant among men indulging in at least 25 drinks a week. Men drinking 40

or more drinks a week had a 33 percent lower sperm concentration than those consuming one to five drinks a week.

Being intoxicated can lead to changes in hormones and other chemicals in the body, including cortisol, glucose, insulin and male hormones, all of which would affect sperm quality, and, poor sperm quality can affect fertility.

A second study published in the journal Sexually Transmitted Infections found that drinking a lot of alcohol was linked to a higher risk of contracting Human Papillomavirus, HPV, a

sexually transmitted disease. HPV can cause head and neck cancers and penile and anal cancers in men, according to the U.S. National Cancer Institute.

The second study included more than 1,300 American men. The researchers found that those who drank the most alcohol (more than 10 grammes a day) were 13 percent

more likely to have any HPV type and 35 percent more likely to have a cancer-related HPV type, compared to those drinking the least amount of alcohol (less than 0.1 gram per day).

Even after taking into account the number of sex partners the men had and whether they smoked—another risk factor for HPV-associated cancers—the study still found an link between alcohol consumption and HPV infection.

Past research has found that moderate alcohol consumption can reduce the body’s ability to defend against viral infections. However, as with the first study, this research was only able to find an association; it wasn’t designed to prove that alcohol definitively caused the increased risk.

Bottom line is that alcohol may have an effect on the immune system, which may increase the risk of HPV. The experts say these findings all point to the importance of limiting alcohol intake among young men. They advise that moderation is best.