Ideally, doctors would like to be able to identify a biochemical marker that they could measure in the culture medium that would accurately indicate the healthiest embryos.

Experts predict such an advance might be available in the next several years. "I don't think that's science fiction," says Ory.

Researchers also are working on a technique called comparative genomic hybridization that aims to improve upon PGD by allowing doctors to remove more than one cell from an embryo and examine all 23 chromosomes, says Surrey.

Freezing a woman's future?
Another hot area of fertility research is egg-freezing, which would allow young women to store healthy eggs and then thaw them out when they're ready to have kids — perhaps 10 or even 15 years down the line. It also could benefit women with cancer who are about to undergo treatment that would destroy their eggs.

The field has been plagued by problems though, because unlike sperm and even embryos, eggs are much more fragile and don't freeze well. But recent quick-freezing advances are allowing doctors to get better results, and an estimated couple hundred or more babies worldwide have been born from frozen eggs that have been thawed and fertilized. Experts predict egg-freezing will be a much more common — and successful — practice within the next decade, perhaps within the next several years.

"There are some encouraging experiments but to date not enough programs have reported on good enough experiments for us to endorse it as a standard technique," says Ory, "but I think that day is rapidly approaching."

For now, though, experts caution that women should view egg-freezing with their eyes very much wide open.

Scott says his fear is that 24-year-olds will come into his clinic, freeze their eggs and then return at 45 — an age when it's very unlikely they'll conceive on their own — and not be able to become pregnant with the frozen eggs either.

"Egg-freezing is a way to hedge your bet but it’s not an absolute guarantee,” he cautions.

Interactive Baby-making by the numbers: Stats on women in the workplace, the rate of assisted reproduction, numbers of twins and triplets, and much more.

Plus, pregnancies at older ages carry more dangers, including the development of gestational diabetes and hypertension. And no one knows whether the children born from frozen eggs might face increased health risks.

Uterine transplants are another approach being explored on the fertility front. Theoretically, they would allow women without a healthy womb, either due to disease or because she was born without one, to bear children. But the surgery would be a major undertaking that would require a woman to take anti-rejection drugs that could pose a risk to a fetus.

In 2000, doctors in Saudi Arabia announced they had performed a uterine transplant in a woman, but the organ had to be removed after three months because of blood-clotting problems. Earlier this year, doctors at New York Downtown Hospital said they are making plans to do the first uterine transplant in the United States. Experiments in rodents have shown that uterine transplants can yield offspring.

Also in the future, though probably still a long way off, doctors might one day use stem-cell technology to produce sperm and eggs in the lab, allowing a man or woman who otherwise can't reproduce their own biological children to do so. Experiments have shown that human egg and sperm can be artificially grown, though no babies have been created.

And as for all those lingering fears that doctors will one day produce babies by cloning their parents, it seems we're no more likely to see that scenario play out today than we were 10 years ago when Dolly the cloned sheep made her debut.

Mainstream scientists aren't going down this path because of all the health and ethical concerns involved.

"No one wants to do reproductive cloning," says Scott. "It is scary.”

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