Does alcohol or smoking reduce male fertility?

Yes. Both can have direct toxic effects at level of testicles. Smoking can create "oxygen radicals" that can directly effect sperm membranes and function of sperm. Both can have indirect effect at level of hypothalmus and pituitary, particularly alcohol, and effect stimulation properties on testicular production of sperm. Lastly, from testicles to ejaculation is 90d, thus effect can be long lasting!
Decreases chances! Studies have shown fertility treatments, particularly ivf are 50% less successful when one or both members of a couple smoke. In addition to decreasing the chance of conceiving, children that grow up in homes of smokers have higher incidences of asthma, respiratory problems, and require more frequent visits to pediatricians for illnesses.
Yes. While the data are difficult to break down fully, it should make intuitive sense. Tobacco (and for that matter marijuana) contains hundreds of toxicants which can interfere with sperm dna. Alcohol use should be limited to a few drinks per week.

Related Questions

Fertility: does drinking alcohol in moderation affect male fertility?

Probably, yes. The real issue is in defining "alcohol use in moderation". For many this means daily alcohol intake of 1-4 alcoholic beverages, which is significant. Alcohol use can effect male hormone metabolism which in turn can effect hormone production. Some data suggest a lower take-home baby rate with ingestion of >4 drinks per week. Read more...
Unlikely. While moderate alcohol use may not directly affect male fertility, if there are other factor that may affect one's liver and hormonal metabolism, then it may be possible. A relatively simple first step is to obtain a semen analysis, which would identify male factor infertility. If abnormal, a full evaluation by urologist is recommended. Read more...

How do you increase male fertility for someone who doesn't want to quit smoking, but has an overall healthy diet and is physically healthy?

Antioxidant therapy. Tobacco use in males significantly impairs fertility. It is very important for the male to stop using tobacco to improve fertility. Cutting down on intake of tobacco products can help. Taking antioxidant therapy like vitamin c, coenzyme q and other antioxidants can help. State department of health quit lines can assist in stopping smoking/chewing tobacco. Read more...
Quit smoking! Think of it this way. If you quit smoking, two things happen: (1) fertility is improved and (2) you live longer. So, do it for the kid and do it for the partner. As you try to quit, try some good, organic, antioxidant supplements: http://www.Essbeg.Com/forhim.Htm. Read more...