Like polio and smallpox, rubella, also known as German measles, has virtually been eliminated in the United States.

When the last epidemic swept the country 40 years ago, many pregnant women experienced such mild symptoms they didn't even know they had rubella, but an estimated 20,000 of their babies were born with a host of serious health problems. Now, an unknown number of those "rubella babies" may get even sicker as adults.

Stephen Wenzler, 39, was a "rubella baby." He was born with congenital rubella syndrome or CRS. He grew up deaf with limited vision and a heart defect. Now, as an adult, he has more health problems.

"My vision became fuzzy and I already had a corneal transplant but it didn't appear to be working well. Very recently, my family doctor discovered I have type two diabetes," Wenzler said through a translator.

At the Helen Keller National Center for Deaf-Blind Youth and Adults, Nancy O'Donnell heard many tales of adult rubella children developing serious late-onset medical conditions. She surveyed the center's more than 900-case database.

"We found high instances of diabetes in the group, glaucoma, and we also found esophageal problems, gagging, vomiting, problems with eating, some thyroid disorders, hormonal problems and in very rare cases a degenerative process in the whole body," O'Donnell said.

Everyone wondered: Could these adult problems be linked to rubella?

O'Donnell said, "If we could get that documentation then it would really improve the kinds of services and care, in terms of long term care as well."

O'Donnell is spearheading a project with the CDC to find out if biological markers of the rubella virus persist in the body into adulthood. Such markers could be used to definitively diagnose the condition.

Despite his medical uncertainties, Wenzler is getting ready for a career in computers.

"I'm planning to go out into the world of work and I wanna fully function out there," Wenzler said.

Knowing what to expect with his health could be a big help in planning his future.

During this year's 40th anniversary of the last U.S. rubella outbreak, the Helen Keller National Center hopes to raise awareness of CRS and spur the medical community to do more research.