Fertility

Drinking alcohol can affect performance in the bedroom because the drinker's not fully in control of their body. Alcohol lowers the sperm count; and heavy drinking can cause temporary impotence.

Alcohol affects judgement too, so couples may have unsafe sex, increasing the risk of sexually transmitted disease or a long term commitment your weren’t planning for! 

Heavy drinking may lower testosterone levels in men and reduce the quality and quantity of sperm. It is recommended therefore that men should limit their alcohol intake to no more than one or two drinks a day if a couple is trying for a baby.