The director of Maryland's mental retardation agency called yesterday for a special committee to review a University of Maryland doctor's use of a cancer-causing drug on retarded boys.

In a letter sent yesterday, Bernard Carpenter asked the University of Maryland to check the safety and effectiveness of the drug -- DES, or diethylstilbesterol -- when it is given to retarded boys to curb their desire to masturbate. Dr. Ruth Baldwin, director of the University's Clinic for Exceptional Children, has prescribed DES for that purpose for some 50 retarded Maryland youths over the last 20 years.

The controversial drug has been banned as a feed additive and its use has been limited by the U.S. Food and Drug Administration because of its cancer-causing abilities.

Baldwin said that after a published account described her use of the drug, she was told by Carpenter's office to stop prescribing it. Although she sent notes to her patients this week asking them to stop using the drug temporarily, Baldwin said she is confident any review will find the drug useful.

Although the state's chief doctor for retardation disputes her, Dr. Baldwin says low doses of DES help keep the retarded youths in school because it stops them from masturbating in class.

Further, she said if the state decides she cannot dispense the drug in the government-supported clinics she directs, she'll continue giving the youths DES on her own.

Dr. David Lang, chairman of the University of Maryland's Department of Pediatrics, said he will direct a committee of medical experts from the university and outside community to "proceed immediately" to determine whether the drug should be used.