Smoking reduces the quality of semen: men who smoke have a lower sperm count than non-smokers and their semen contains a higher proportion of malformed sperm.
By-products of nicotine present in the semen of smokers have been known to reduce the mobility of sperm. and to affect their normal swimming patterns.
Genetic material in sperm cells is damaged by smoking. For example, benzoapyrene , one of the carcinogenic components of tobacco smoke, has been found to bind to DNA in sperm, inducing mutations. This damage can persist in embryos