

Sperms have proven their toughness and some negative lifestyle choices have had little impact, new British research has concluded. Drinking, smoking, being overweight and drug-taking haven't had any detrimental effect on the sperm quality of infertile men. Men with unhealthy lifestyles produced as much swimming sperm as those with more sensible attitudes towards life.
The rather surprising findings contradicted advice given to men who have struggled to conceive. Under current guidelines doctors are supposed to warn men diagnosed with infertility of the 'dangers' of alcohol, tobacco and recreational drugs. So its pretty obvious you can't keep a good sperm down
http://www.dailymail.co.uk/health/article-2144909/Sperm-count-men-reduced-exposure-chemicals-environment.html
http://www.dailymail.co.uk/health/article-2140795/Sperm-crash-walls-race-egg.html