Alcohol consumption during pregnancy affects sons sperm concentration

C. Ramlau-Hansen from Aarhus University has just published a new study in the European journal Human Reproduction which gives reason to believe that ingestion of even small amounts of alcohol during pregnancy can damage testicles development of boy foetuses.
The study compares sperm concentration among 347 young Danish men born in 1984-87. The mothers filled out a questionnaire during pregnancy where among other things  was asked about alcohol intake during pregnancy.
The sperm concentration of the sons in 2006 showed that boys born of mothers who drank more than 4.5 drinks a week have 32% lower sperm concentration than sons of mothers who drank less than 1 drink per week.
There was no statistical difference in sperm motility, or the number of abnormal sperm. Sons own alcohol consumption had no influence on the outcome, and it was also adjusted for maternal smoking during pregnancy.
Alcohol is a cell poison which passes through the placenta into the fetal bloodstream. Animal studies have shown that alcohol has a toxic effect on sertoli cells in the testicles. These are the cells responsible for sperm production.
It is not unexpected from the literature, that exposures during the time period of testes development may impair spermatozoa production 20 years later in life.