Fairfax County seventh and eighth graders would be offered lessons on AIDS beginning next semester if the county School Board approves a proposal presented last night.

The county began teaching high school students about acquired immune deficiency syndrome last year, becoming one of the last area school systems to do so.

The board heard a staff proposal last night to offer lessons to seventh and eighth graders about sexually transmitted diseases, including AIDS, with parental permission. Classes for boys and girls would be offered separately.

In the ninth grade, where AIDS instruction is now offered as part of the general education program, with variations from school to school, all students would be taught about AIDS as part of a new unit in their coeducational health classes, with parental permission not required.

School Board members did not comment on the proposal, but they are likely to approve some version of lessons for intermediate school students because they requested the curriculum proposal. Community groups have pushed for the earlier lessons as well.

The board is to vote on the proposal at its Dec. 3 meeting. The curriculum materials are available for public viewing through the School Board office, and public responses to the lessons will be collected before the vote.

To approve the new lessons, the School Board would have to lift its policy prohibiting teaching about homosexuality or contraception before high school.

AIDS destroys its victims' immune systems, leaving them vulnerable to cancers or other diseases. It is transmitted via blood or bodily fluids. Most victims in the United States have been homosexuals or drug abusers.

The county's AIDS lessons would emphasize that abstinence from sex or intravenous drugs are the best ways to avoid getting the disease, but would teach that condoms and spermicides should be used by those who are sexually active.

Fifth and sixth grade teachers would be trained to answer student questions about AIDS in a limited way, Assistant Superintendent Mary Anne Lecos told the board.