A University of Maryland medical school professor regularly prescribes daily doses of DES, a female sex hormone known to cause cancer, blood clots and other adverse effects, for retarded male adolescents in an attempt to stop them from masturbating in school classrooms.

The unorthodox and unapproved drug treatment has been dispensed for the last 20 years by Dr. Ruth Baldwin, 64, a clinical professor of pediatrics and director of the University of Maryland's Clinic for Exceptional Children in order to keep the youths from being expelled from their special classes in public schools in Salisbury, Hagerstown and Baltimore.

"I have a lot of males on it," said Dr. Baldwin of DES. "It reduces the reaction of their male sex hormones.

Diethylstilbesterol, or DES, has been a source of controversy in medical and scientific circles for more than a decade because of evidence that it can cause cancer in women and their male and female offspring. As a result of years of unfavorable studies, the U.S. Food and Drug Administration has limited DES use in males for prostate and breast cancer. The Maryland use is so novel the FDA was unaware of it.

"That usage has not been approved by the FDA," said Wayne Pines, the agency's spokesman, who said the government considers the drug a carcinogen in humans. "But the FDA does not have any authority to take any action against a doctor who uses an approved drug in an unapproved way."

Critics of DES say its cancer-causing qualities should prevent doctors from prescribing it for any unapproved use. And specialists who work with the retarded say disruptive behavior is best corrected by psychological help, rather than administering drugs.

"I would consider that it is harmful," said Dr. Barbara Hudson, medical consultant for the Maryland Mental Retardation and Developmental Disabilities Administration and a doctor at the Rosewood Center, Maryland's state hospital for the mentally retarded. "There are no drugs that will change masturbation. All it does is create big breasts in the boys."

The retarded youths are given the female hormones for five to six years, beginning at age 15, according to Baldwin. "Masturbation is a terrific problem" for the retarded teen-agers, she says, because "they would masturbate in school in front of everybody. When the teachers try to stop them, they would become wild."

Baldwin said the drug reduces male sex hormones to the point where the teen-agers have little desire to masturbate. "We're not sterilizing them," she said. "When you take them off it, within a day or two they're potent again."

DES's cancer-causing qualities do not trouble her, she said, because "these children are those who have a short life span anyway. It would be very unusual for any of them to develop cancer at those low doses."

But an FDA scientist says the cancer potential of DES on males is unknown at any dosage. "As far as induction of cancer in males, we have no studies," said Dr. Solomon Sobel, director of the Division of Metabolism and Endocrinology within the FDA's Bureau of Drugs.

But other side-effects besides cancer are cause for concern. "Even small doses can have side effects," Sobel said, "such as production of breasts, stunting growth by closing growth centers in the long bones; all the feminizing effects."

Changes in blood coagulation also is a possibility, he said. A decades-old experiment where DES was used to treat severe acne was stopped because of these "very unfavorable" side effects in males, Sobel said. The other major study of DES in males, a 1965 National Institutes of Health project involving heart-attack victims, also was ended early, because of excess cardiovascular problems.

Baldwin said that the youths have not experienced any ill effects other than slight swelling of the breasts in some boys. She added that the youth's parents do not ask questions about the drug, but readily agree to have their sons take it. "Parents don't care," she said. "They want to keep the children at school so the mother isn't tied down."

"Doctors say they the retarded can learn to stop masturbating excessively with discipline," said Baldwin. "But it's difficult to discipline the retarded," she said, adding that she prefers DES to psychotropic drugs she says are used by other doctors to correct masturbation, like Valium, which make the youths too sleepy to concentrate on their schooling.

Although the FDA has a procedure where doctors can use approved drugs in experimental fashion by filing an application, Baldwin has not done so. She does plan to compile her results into a medical journal article, she said.

Baldwin said she has given the drug to "about 50" retarded boys in the last 20 years who have sought help from the main clinic in Baltimore and its satellite offices. In several cases, the doctor personally drops off the medicine at the youths' homes because local doctors won't prescribe the drug.

Using DES to curb masturbation is an outdated therapy, Hudson said, and one she ordered ended throughout the state a decade ago after medical journals found it to be worthless. "When I first came to Rosewood, I can't tell you how many boys were receiving injections weekly. It was as common as asking for a hysterectomy for a mentally retarded young girl. I stopped it immediately."

She said she was "distressed and surprised" to learn DES was being administered to retarded youths. "From a medical standpoint, it raises concerns."

Baldwin said she will continue to give the drug despite the fact state mental retardation officials oppose its use. "It's been very successful. Anything I can do to help them, I will."