Infertility is defined as a couple's inability to become pregnant after one year of sex without using birth control. When considering whether you may have an infertility problem, however, bear in mind that "normal fertility" is defined as the ability to naturally conceive within two years' time. Sometimes it's a matter of determining when you are most fertile. If you are not sure when you ovulate, use this interactive tool to calculate your peak fertility.

Of all couples who have not conceived after one year, about half will go on to conceive naturally in the following year.If you are a younger couple, this is encouraging news. However, if you are 35 or older, another year may be too long to wait before seeking testing and treatment.

A woman's fertility declines from her mid-30s into her 40s, as her egg supply ages. At the same time, her risk of miscarriage increases. Although a man's sperm count decreases with age, male fertility is not known to be greatly affected by age.