Reprinted from: Stay Fertile Longer: Everything You Need to Know to Get Pregnant Now -- Or Whenever You're Ready by Mary Kittel with Deborah Metzger, M.D., Ph.D. © 2004 by Rodale Inc. (September 2004; $13.95US/$19.95CAN; 1-59486-053-X)

Mary Kittel is a seasoned health writer and coauthor of numerous books, including The Hormone Connection and Prevention's Ultimate Guide to Women's Health and Wellness.

Deborah Metzger, M.D., Ph.D., is a leading expert in the field of fertility and reproductive health. She is medical director of Helena Women's Health in San Jose, California, and was previously associate professor at the University of Connecticut Health Center. She is an advisor to the national Endometriosis Association and has lectured extensively throughout the world.

Permission granted to Pregnancy.org, LLC by Rodale, Inc., Emmaus, PA 18098.