SAN JOSE, Calif. (AP) _ Women who interrupt careers for family reasons, including child-raising, never again make as much money as female peers who stay on the job, the authors of a new study said Friday.

Over time, the women career ''gappers'' make up some of the wage differences, but even 20 years after returning to the work force they take home smaller paychecks than women who never left, the study found.

''These women gappers partially rebound, but never catch up,'' said Joyce Jacobsen, coauthor of the study and an economics professor at Rhodes College in Memphis, Tenn. ''Part of the problem is that employers think that these women who left aren't as serious about their jobs.''

Coauthor Laurence Levin, an economics professor at Santa Clara University who first worked with Jacobsen when they were graduate students at Stanford University, said employers think ''gappers'' are bad investments.

''If you leave the workforce, that signals to some employers that a woman might not be as good a worker,'' Levin said. ''Or when a woman who had a baby comes back to work, an employer might think she's got her mind on her baby and her home life instead of her job.''

Besides perceptions, the study presented last week to the American Economic Association conference in New Orleans also cited three reasons why ''gappers'' don't catch up financially.

-Women who leave the labor force lose seniority and thus earning ability.

-Women who have career interruptions miss on-the-job training.

-Women who stay away from jobs too long might forget skills.

The study scrutinized 2,426 career women interviewed eight times between 1984 and 1986. Their ages ranged from 30 to 64 and each had one or two work gaps over a 20-year period of at least six months each.

The average gap was 7.5 years, and 85 percent of the women said they interrupted careers for ''family reasons.''

Levin said it appeared that women who took a shorter break of one year or so lost the same ground as women who stopped working for longer periods.

The findings showed the wage gap was 33 percent during the first year a woman returned to work after a career interruption. That gap shrunk to 20 percent after 3-5 years back on the job. After 11-20 years back to work, the ''gappers'' still made 10 percent less than their peers. After 20 or more years back at work, the wage gap was 7 percent.

In one research example, a woman who entered the work force at age 21, then quit at age 25 for seven years to have two children, made $52,000 less over the next 10 years compared with peers who stayed on the job.

''It's not totally disastrous for a woman to interrupt her career, but it's going to cost her,'' said Levin, whose subjects' careers ranged from ''pink collar office jobs'' to college-educated professionals.

A few previous studies, using data from the 1970s, had similar findings but not on such a broad scale, the researchers asserted.

Jane Porter, a veteran corporate consultant who for 10 years headed the human resources department at the Wall Street firm Salomon Brothers Inc., said employers can bridge the pay gap by helping women who take time off.

Companies can build day care centers at the office, allow flexible work schedules and job sharing and provide special training, she said.

''Employers can get the same bang for their buck if they know how to help workers make up for lost time,'' she said.

''The perception that a person might not be 100 percent mentally committed to their job after a break is tougher to fix,'' she said. ''But it's possible to convince employers that someone who wants to be home by 6 is just as dedicated as someone who works 80-hour weeks.''