As a woman, you may feel solely responsible for your inability to conceive. However, infertility is not just a female problem. In fact, nearly 40 to 50 percent of infertility cases involve factors related to the male. In 10 to 35 percent of cases, both the female and the male have a fertility problem. Another 15 to 20 percent of cases are said to be unexplained - meaning doctors don't have a concrete reason for a couple's inability to conceive.
In women, the most common causes of infertility involve ovulation factors and diminishing supply of quality eggs. Most women ovulate normally into their late twenties; however, by age thirty-five to thirty-eight the ability to ovulate normally may decline. Ovulation may also be affected by factors such as thyroid problems and hormone imbalances. Other major causes of female infertility involve problems with fallopian tubes, cervix, and/or uterus.
In men, the focus is on the quantity and quality of sperm. Age is not usually a factor in a man's ability to produce sperm, however, any damage to his reproductive organs can cause problems with sperm production and delivery.
In addition, certain lifestyle factors may affect the ability of both sexes to conceive. For example, in women, Chlamydia infections, and other sexually transmitted diseases (STDs) can damage fallopian tubes, resulting in infertility. In men, the use of alcohol, marijuana, and other recreational drugs has well-documented harmful effects on sperm production.
Smoking tobacco may or may not be harmful to reproduction. Some studies show that nicotine and other chemicals from smoking can impair the ovaries and interfere with their ability to create estradiol, the hormone specifically involved in egg production. In fact some estimates are that tobacco use reduces fertility in both females and males by about 15 percent. Other research however, shows no evidence of this effect.
Keep in mind that couples aren't tested for infertility simply because they drink alcohol or smoke. They're screened for infertility because they've been unsuccessful in their pregnancy attempts. Previous behaviors may come up in evaluation, but there are likely other reasons for the problem.