Alcohol
Alcohol consumption needs to be evaluated carefully:

Red Wine: Drinking 100 ml of red wine daily is generally not a problem. Studies on mice have shown that those given a small amount of red wine daily lived longer than those that didn’t.
Beer: Drinking one can of beer daily is also considered acceptable.
Hard Liquor: Avoid it as much as possible.
It’s essential to drink in moderation and avoid getting drunk. For individuals with gout, alcohol should be strictly avoided. Doctors recommend refraining from alcohol during the preconception period because alcohol harms the liver. Among individuals with poor liver function, around 70% experience sperm maturation issues or loss of sperm motility.

Smoking
Smoking is harmful and contains over 1,000 chemicals, nearly 100 of which are carcinogens. The most harmful component is nicotine, which can directly damage the testes.

The testes, where sperm is produced, can be thought of as the “factory” for sperm. The seminiferous tubules are the “workshop” within the factory. Nicotine damages this “workshop,” reducing production speed and increasing defective sperm, ultimately affecting sperm quality and quantity.

Conclusion
For optimal fertility, avoid smoking and minimize alcohol consumption, especially during the preconception period.