The McCaughey septuplets have become the poster babies for the age of multiple births. But as adorable as they look on magazine covers, there is a sad reality in their lives that all too often accompanies the birth of more than one baby at a time.

Three of the Iowa septuplets are suffering serious health problems. Alexis has a disease that causes muscular weakness in all four limbs, and she does not have the strength to walk or sit up independently. Nathan has a condition that causes spasticity in his legs, and his lower body and leg muscles have been rigid since birth. Scans show they both have underdeveloped areas of the brain. Both Alexis and Natalie suffer fromsevere acid reflux and are being fed through tubes in their stomachs.

Incidents of multiple births have been increasing rapidly since 1996, when the number of babies born in sets of three, four or more jumped by 19 percent. In 1971, there were about 1,000 babies born worldwide with two or more companions. By 1996, that number was more than 5,000, including 560 sets of quadruplets and 81 sets of quintuplets. Experts attribute the phenomenon to the fact that women are waiting until they are older to have children, which make them more likely to have multiple births and more likely to use fertility treatments that cause the release and fertilization of multiple eggs.

About 6 percent of single babies are born at low birth weight, but more than half of twins are. And the percentage rises dramatically as the number of babies goes higher. "The major problem relates to prematurity," says Zev Rosenwaks, a doctor at Cornell University Medical Center and one of the country's leading experts on infertility. The more babies involved, the greater the likelihood they will be quite premature, he says.

Rosenwaks was among the infertility experts who attended a recent conference sponsored by the National Institutes of Health and the Geneva-based Bertarelli Foundation, formed in April to support research and education on the human and social aspects of infertility and new technologies for treatment. The meeting looked at "how we can eliminate or diminish high-order multiple births," he says. "Eight or seven babies at a time is not a desirable outcome."

Those numbers generally occur when fertility drugs cause numerous eggs to be released that are then fertilized naturally. "With good monitoring and blood tests one can diminish this," Rosenwaks says. Drugs are given in stages and if too many eggs are released, for example, the treatment cycle can be canceled or interrupted. If the patient releases multiple eggs,treatment can then shift to in-vitro fertilization, and the number of embryos transferred back into the patient is limited. "We freeze the rest for future cycles," he says.

Some consensus is emerging among infertility experts on how many eggs to implant, Rosenwaks says. Women younger than 33 have a 35 percent success rate with implanted eggs. "You don't have to transfer four or five embryos," he says. "You can reduce the number to two, and at most, you get twins. Women over 40 have lower implantation rate. They are not at as great a risk when you transfer more than three embryos."

Some countries allow only three eggs to be transferred, which Rosenwaks feels is not desirable because it puts women who are older at a disadvantage. Older women are more likely to be infertile. "The consensus [at the conference] was to individualize the number of embryos transferred based on [a woman's] age and embryo quality, to diminish the risk of high-order multiples," Rosenwaks says.

One of every six American couples experiences infertility, and half undergo treatment, which can involve $10,000 or more per treatment. Some insurance plans pay; many do not. A survey commissioned by the Bertarelli Foundation and conducted by Peter D. Hart Research Associates found that about 60 percent of Americans feel insurance companies should pay for infertility treatment, but about half expressed reservations about the health problems that so often accompany multiple births. They supported limiting the number of embryo implants to avoid those medical complications.

People in the survey were surprisingly compassionate toward couples dealing with infertility and the possibility of multiples, says Geraldine A. Ferraro, who is on Bertarelli's board. She said a goal of the conference was to make absolutely sure "that people who are using fertility drugs or artificial insemination do it with caution and care and responsibility so they don't produce significant numbers of children at one birth. . . . The foundation is not looking for regulation but for responsible procedures being done by doctors who are thinking of the next step."

The anguish surrounding multiple births surfaced in a conversation she had with a young woman who'd had a failed implant. The young woman begged her doctor to implant four eggs the next time, instead of three. He agreed on the condition that if all four were successfully implanted, she would agree to a reduction of one. This is a far different situation than aborting an unwanted pregnancy, Ferraro notes. These babies were very much wanted. "In this instance, you've got women who've spent a lot of time and money," Ferraro says, "and there's a lot of emotion tied up in this pregnancy."

Couples who have had children easily can't possibly understand the devastating sense of loss felt by couples diagnosed as infertile. Over the last 20 years, enormous medical progress has been made in treating infertility. With sophisticated techniques, it is possible to reduce the chances of multiple births, prematurity and the other problems that so often occur. This is the responsible way to use the medical technology that can bless couples with the miracle of birth.