You'll never really know if you'll have fertility issues until you try to conceive. But if you're under 35 and have been trying for more than a year, talk with your gynecologist. She may be able to pinpoint a specific problem or refer you to a reproductive endocrinologist who specializes in the diagnosis and treatment of infertility. If you're 35 or older, put yourself on a shorter schedule: "Get help if you haven't conceived in six months," says Daniel Potter, M.D. "No matter how young you look, if you're 40, your eggs are still 40." For more information or support, go to the National Infertility Association's Web site, resolve.org.