BOSTON -- Fertility treatments have greatly increased the chances that families will have multiples, triplets, and even quadruplets.

The number of babies being delivered prematurely has also increased. About 15 years ago, premature babies had just a 20 percent chance of surviving. Today, the odds have grown to nearly 90 percent, but that progress has come at a price, reported WCVB-TV in Boston.

Twenty-five to 50 percent of preemies will have learning or behavioral disabilities.

"About 10 to 15 percent of the preterm babies that we see will go on to develop some form of cerebral palsy," said Dr. Adre du Plessis, of Children's Hospital Boston.

William Watson, 10, fights cerebral palsy's effects every minute of every day.

"Well, I have a pelvic obliquity, so my muscles are kind of like elastics," William said.

For William, boxing is both physical therapy and an outlet for pain.

"This is the stage of his life where the differences are beginning to become more obvious," William's mother, Lori Watson, said.

What he really wants is to walk, but that's a leap he's been unable to make.

"It kind of gets frustrating to me after a while," he said.

William is not alone. Doctors say the cerebral palsy rate will continue to rise until they can predict which premature babies will suffer the brain injury, which right now they can't do.

"The babies could be having the injury right in front of your eyes, and you wouldn't know it. And there is currently no technique for being able to pick that up," du Plessis said.

But researchers think they are on the verge of a breakthrough.

"It involves shining near infrared light across the skull and into the brain," du Plessis said.

A type of monitoring detects abnormal blood flow in babies' brains. Du Plessis said that treatment with medicine could lead to prevention.

"That is our goal -- to be able to identify at-risk babies and then to monitor them continuously during the period of risk and to identify them before the irreversible injury occurs," du Plessis said.

For William, there is no cure. But he and his doctors hope that with strong will and intense therapy, he'll walk.