Infertility is far more common than most people think. According to the American Society of Reproductive Medicine, approximately 6.1 million couples in the United States — about 10 percent of the reproductive-age population — experience fertility problems. For these couples, becoming pregnant is far from easy.

The truth is that hundreds of variables must coincide precisely for conception to occur and for a woman's body to successfully maintain a pregnancy for nine months. The average couple, ages 29 to 33, with no fertility problems, has about a 20 to 25 percent chance of getting pregnant in any given month (or menstrual cycle).

There is no "typical' infertile patient. Ovulation and sperm deficiencies are the most common infertility problems, accounting for two-thirds of all cases.

When ovulation fails to occur, no egg is available for fertilization. The most common symptoms of ovulatory problems are irregular menstrual periods or the absence of menstrual periods.

Less common fertility problems for women include structural problems or scarring of the fallopian tubes and/or uterus caused by pelvic inflammatory disease or endometriosis (a condition causing adhesions and cysts), uterine fibroids or congenital (birth) defects.

Sperm deficiencies can include low sperm production (oligospermia) or lack of sperm (azoospermia). Sperm may also have poor motility — they don't move properly once inside the female reproductive tract to achieve fertilization. Additionally, sperm cells may be malformed or may die before they can reach the egg.

About one-third of infertility cases can be attributed to male factors, and about one-third to factors that affect women. Roughly one-third of infertility is couple-related, with a combination of problems in both partners impeding fertility.