Alcohol Use: Drinking alcohol can lower testosterone levels, cause erectile dysfunction and decrease sperm production. Liver disease caused by excessive drinking also may lead to fertility problems.
Tobacco Smoking: Men who smoke may have a lower sperm count than do those who don't smoke. Secondhand smoke also may affect male fertility.
Emotional Stress: Stress can interfere with certain hormones needed to produce sperm. Severe or prolonged emotional stress, including problems with fertility, can affect your sperm count.
Use of Recreational Drugs: Drugs like cocaine, marijuana, opium may cause fertility problems. Cocaine use by men has also been linked to abnormal development in subsequent offspring. Marijuana can also affect sperm function. Research has shown that sperm motility and the sperm’s ability to bind to an egg can be adversely affected by consistent exposure to marijuana. Anabolic steroids taken to stimulate muscle strength and growth can cause the testicles to shrink and sperm production to decrease.
Excessive Exercise: Proper exercise is important to maintain a desired weight and general level of fitness. Excessive exercise however, can lead to reduced fertility in both males and females. In men, excessive exercise has been associated with reduced sperm production. In women, too much high intensity exercise can lead to the cessation of ovulation. In should be noted that in most couples moderate exercise will not affect their fertility. Reproductive disorders that result from excessive exercise can usually be reversed by making adjustments to the amount and type of exercise undertaken.