Moderate weekly alcohol intake may adversely affect sperm quality in healthy young men, according to a recent study.

Researchers found that Moderate alcohol intake of at least 5 units every week is linked to poorer sperm quality in otherwise healthy young men. And the higher the weekly tally of units, the worse the sperm quality seems to be.

"This is, to our knowledge, the first study among healthy young men with detailed information on alcohol intake, and given the fact that young men in the western world [drink a lot], this is of public health concern, and could be a contributing factor to the low sperm count reported among [them]," researchers said in the study.

The research team based their findings on 1221 Danish men between the ages of 18 and 28, all of whom underwent a medical examination to assess their fitness for military service, which is compulsory in Denmark, between 2008 and 2012.

As part of their assessment, the military recruits were asked how much alcohol they drank in the week before their medical exam (recent drinking); whether this was typical (habitual); and how often they binge drank, defined as more than 5 units in one sitting, and had been drunk in the preceding month.

Researchers found that drinking alcohol in the preceding week was linked to changes in reproductive hormone levels, with the effects increasingly more noticeable the higher the tally of units.

Testosterone levels rose, while sex hormone binding globulin (SHBG) fell; similar associations were also evident for the number of times an individual had been drunk or had binge drunk in the preceding month.

Forty-five percent of the men said that the quantity of alcohol they drank in the preceding week was typical of their weekly consumption.

The effects were evident from at least 5 units a week upwards, but most apparent among those who drank 25 or more units every week.

And total sperm counts were 33 percent lower, and the proportion of normal-looking sperm 51% percent lower, among those knocking back 40 units a week compared with those drinking 1 to 5 alcohol units per week.

"It remains to be seen whether semen quality is restored if alcohol intake is reduced, but young men should be advised that high habitual alcohol intake may affect not only their general health, but also their reproductive health," researchers concluded.

The findings were published in the British Medical Journal.