Toxic effects related to tobacco, marijuana, and other drugs
Smoking may cause infertility in both men and women. In experimental animals, nicotine has been shown to block the production of sperm and decrease the size of a man's testicles. In women, tobacco changes the cervical mucus, thus affecting the way sperm reach the egg. It also increases the risk of an ectopic pregnancy by affecting the fallopian tubes.
Marijuana may disrupt a woman's ovulation cycle (release of the egg). Marijuana use affects men by decreasing the sperm count and the quality of the sperm.
Every family has that one kindly aunt and uncle who "never had any
children." And, until you yourself have struggled with infertility, you probably never
wondered why they had no children; you just accepted it. Well, if that aunt and
uncle of yours are now seniors, in their day they could have adopted from a
wide assortment of newborns. But they didn't. Today, they probably live
comfortably in a small condo somewhere, travel a great deal, are enjoying their
retirement, and dote on a large selection...
Heroin, cocaine, and crack cocaine use induces similar effects but places the user at increased risk for PID and HIV infection associated with risky sexual behavior.
In women, the effects of alcohol are related more to severe consequences for the fetus. Nevertheless, chronic alcoholism is related to disorders in ovulation and, therefore, interferes with fertility. Alcohol use by men interferes with the synthesis of testosterone and has an impact on sperm concentration. Alcoholism may delay a man's sexual response and may cause impotence, the inability to have or sustain an erection.