The exposure of parents to chemicals at work may cause brain tumors in their children, according to a new study at the University of Southern California Medical School.

If the results of the new study were extrapolated to the society at large, it could mean that the chemical exposure of parents accounts for 25 percent of all the childhood brain tumors in the country, according to Dr. John M. Peters, who led the study.

The study is the first to show a relation between parents' occupation and brain tumors in children, according to Dr. Alan Leviton of Harvard, a specialist in childhood brain tumors who is working on a smiliar comparison. He and others say the study is important in establishing the cause of childhood brain tumors and the hazards of workplace chemicals.

The study took 92 children with brain tumors and examined the occupational exposure of the children's parents, then compared that with a similar group of healthy children and their parents from the same Los Angeles neighborhoods.

Parents of children with brain tumors had three to 10 time more exposure to chemicals at work than the parents of healthy children, Peters and his coworkers, Susan Preston-Martin and Mimi Yu, wrote in an article published today in Science magazine.

"We started off knowing almost nothing about the causes of brain tumors in kids. It is the second leading cause of death among children, after leukemia," they say. This study gives some clues about where to look for causes, although the specific agents of disease in the workplace are still uncertain, the article says.

The most striking finding of the study was that a very large number of the children with brain tumors had parents who work in the aircraft industry in Los Angeles. Of 92 families with a diseased child, 10 fathers reported working in the aircraft industry. Among the 92 control families none reported working in the aircraft industry.

Peters could not say whether the aircraft industry has any more hazardous environment than similar industries. He said he has begun to work on follow-up studies in and out of the aircraft industry to give more detail about some of the chemicals parents are exposed to at work.

On other questions of exposure, the study found seven times more workplace exposure to paint fumes, and three times more exposure to chemical solvents among fathers of diseased children than among fathers in the control group.

It also found three times more exposure to chemicals among mothers of diseased children than among mothers in the control group.

Peters said that the disease might have been passed to children from fathers either through genetic damage in the father's reproductive system, or more directly, by such things as chemicals clinging to a father's clothing when he comes home.

For mothers, the exposure during pregnancy or nursing could have a direct effect on fetus or infant.