Infertility is defined as the inability to conceive a child despite trying for one year.
The condition affects about 5.3 million Americans, or 9 percent of the reproductive age population, according to the American Society for Reproductive Medicine. Lifestyle can influence the number and quality of a man's sperm. Also, environmental toxins, including pesticides and lead, may be to blame for some cases of infertility. The causes of sperm production problems can exist from birth or develop later as a result of severe medical illnesses, including mumps and some sexually transmitted diseases, or from a severe testicle injury, tumor, or other problem. Inability to ejaculate normally can prevent conception, too, and can be caused by many factors, including diabetes, surgery of the prostate gland or urethra, blood pressure medication, or impotence.