It all depends. Want more? Read on.

When is it too late to have a baby? That depends on whether you're looking at it from the female's perspective or the male's physiologically speaking, that is.

While a man's reproductive potential declines at the pace of a canoe easing down a lazy river (fertility continues well into his 70s or 80s), a woman's fertility begins a gradual decline when she hits 30, picks up momentum at 35, then hits speed-boat velocity at 39. By age 45, 80-90 percent of women are infertile.

If a 45-year-old woman does conceive, she has about a 40-50 percent chance of miscarrying. If the child is born, there is a three percent chance of Down's Syndrome and a two percent chance of other chromosomal abnormalities.

With fertility's limited and unpredictable duration, women are often challenged to choose motherhood over career or even search more diligently to find the best partner to share in parenting. So what are the options for women who have delayed childbearing but now want a baby?

Once a woman makes the decision to conceive, it's important that she receives counseling on nutrition, infectious disease avoidance and genetic screening. In Jewish couples, screening for Tay Sachs, Cystic Fibrosis and Canavan's Disease is encouraged. For women 35 and older, fertility evaluation is recommended if there's no pregnancy after six months of trying.

Once the infertility cause is identified, treatment options can be addressed.

For any treatment, consider this: What is the chance for success with this particular treatment? To highlight the age factor, national 2007 delivery rates for 35- to 37-year-old women who had in vitro fertilization, or IVF, were 30.5 percent per cycle. For women 41-42, it drops to 11.7 percent, and for women ages 43-44, the rate plummets to 4.6 percent.

Advancing age definitely influences egg quality and to date, little can be done to improve this. Shocking? Yes, considering the well-publicized successes of entertainers who conceive in their late 40s and the dramatic reports of women delivering babies in their 60s. The truth, however, is that in most of these situations, donor eggs helped achieve these healthy pregnancies.

Donor eggs are typically obtained from healthy women under 30. Their eggs are fertilized with the husband's sperm and placed back into the mother's womb after hormonal manipulation. It's an expensive procedure and the mother actually has no traditional genetic influence on the baby.

Yet for the 43-year-old woman trying to conceive, her delivery rate per IVF cycle goes from five to 55 percent with donor egg use. This highly successful treatment option is often not desirable for women with reduced or absent ovarian function, however, given the absence of a genetic tie to the mother.

For women who choose to delay parenting, the future may well be with oocyte cryopreservation, or egg freezing.

While the American Society of Reproductive Medicine officially classifies egg freezing as an experimental procedure, it's still actively pursued by many women.

Whether it's chemotherapy, ovarian surgery, or simply the desire to delay childbearing, young women may choose to undergo ovarian stimulation and subsequent needle aspiration of the ovary to obtain multiple eggs. The eggs are then frozen and can be stored for several years. The procedure works best for women around age 25.

When the woman is ready for pregnancy, several eggs are defrosted and injected with sperm. After confirming fertilization, the embryos are transferred into the mother's womb.

Delivery rates are about five percent per thawed egg, so success rates depend on the number of eggs obtained; repeated harvests improve future success odds.

It's important to note that reported success rates are based on younger women. Women in their late 30s and early 40s can expect much lower conception rates per egg. Currently no techniques truly improve egg quality, so egg freezing is primarily an advance for women in their 20s or early 30s.

Implications of egg freezing for the traditional family are significant. According to the CDC, the birth rate for women 40-44 rose more than 70 percent between 1990 and 2006, and births reported for women 45+ has quadrupled since 1990. Egg freezing availability will eventually accelerate this trend.

So, can we really say when it's too late to start a family? Probably not. If a woman is in good health and willing to accept a slight health risk increase, it's likely she can successfully deliver a healthy child well into her seventh decade. Reproductive technologies continue to provide options for family planning.

Chad Friedman, M.D., FACOG, a reproductive endocrinologist with Ohio Reproductive Medicine in Columbus, Ohio. He has spent more than 25 years specializing in reproductive endocrinology and infertility. He also is an associate professor in the Department of Obstetrics & Gynecology at The Ohio State University College of Medicine.