An "alarming" number of children are being treated at Children's Hospital for sex-related diseases, including herpes, a hospital official said during a panel discussion last week.

Many District children live in "destitute and difficult circumstances" in the city's streets, a second speaker said during the discussion, held at Children's Thursday as part of the D.C. Rape Crisis Center's fifth annual "Anti-Rape Week."

In the forum, entitled "The Psychology of Child Pornography, Child Abuse, and Incest," Joyce Thomas, director of Children's Child Sexual Abuse Victim Assistance Project, said the program treats an average of 300 sexually abused children a year.

"Sexual abuse of children is a rather major problem that affects many families regardless of ethnic and financial background," Thomas told an audience of about 50 who gathered at Children's. "The largest offender in these cases is generally a person known to the family," she warned as she flashed slides of newspaper headlines about sexual assaults on children by adults.

Anti-Rape Week was designated "to make people aware of the ways we can stop rape and to learn of the devastating effect it can have on people and what we can do to support these victims," said Barbara Klestzick of the Rape Crisis Center.

Other programs during the week included a "for men only" forum, "Men Confronting Violence Against Women;" a sexual harassment workshop and a legislative panel subtitled "Strategies to End Violence" in which City Council Chairman David Clarke participated.

Appearing on the panel with Thomas, Dr. John Dillingham, a psychiatrist from the Washington School of Psychiatry, said the children he has treated over the last two years were generally victims of sexual abuse, but also were usually children who fell between the cracks in social service programs. Many had resorted to living on the streets, he said.

"There are youths in Washington living in abandoned buildings, living in destitute and difficult circumstances," Dillingham said.

He considers these children society's "homeless of the future" and describes them as "throwaway children, pushed out of their homes often for economic reasons, but also because they are difficult children. They don't fit well in conventional social services such as special school programs or traditional counseling . They are often caught up in a conflict between two parents.

"They congregate . . . usually at places like bus terminals and porno strips," said Dillingham, who with a couple of assistants interviewed nearly 1,000 of these children in five cities, including the District.

The psychiatrist found that 75 percent of the interviewees had been sexually abused while living with the family and always had a sense of alienation from the family's life style. By the time Dillingham talked to these children, 60 percent of them were suffering from some form of chronic mental illness.

Dr. Chris Courtois, an Alexandria psychologist, treats adults who were sexually abused as children.

"In 1955 it was estimated that there were 1.9 incidents of incest per million people," Courtois noted. "Now some writers say 1,000 per million, some say 1 in 20 families.

"Incest remains taboo," Courtois said. "Although we are talking about it more, it is still not a topic we are comfortable with. The taboo on occurence should remain, but the taboo on talking about it should be lifted."

A benefit concert for the D.C. Rape Crisis Center will be held at the Bayou, 3135 K St. NW, tomorrow from 8 p.m. to 2 a.m. There's a $5 admission charge to the concert, featuring the Insect Surfers, the Dinettes, the Trufax and the Insaniacs.