SAN FRANCISCO, California (AP) -- Occasional, mild spankings of young children are OK and do not cause any lasting harm that carries into adolescence, according to a study released Friday.

Such discipline does not hurt youngsters' social or emotional development, the researchers reported.

"A lot of people out there advocate that any spanking at all is detrimental, and that's not what we found," said study co-author Elizabeth Owens from the Institute of Human Development at the University of California at Berkeley. "We're not advocating this is a strategy that should be used with kids, but we object to people wanting to ban it when we see no evidence that it's harmful."

The study was being presented at a meeting in San Francisco of the American Psychological Association.

Owens and author Diana Baumrind analyzed data gathered from 100 middle-class white families from 1968 to 1980. The children and parents were interviewed, tested and observed on three occasions by two teams of psychologists when the children were 4, 9 and 14.

The study found the majority of families disciplined their preschool children by using mild to moderate spanking. The results showed no negative effects on cognitive, social or behavioral skills of those youngsters and found no difference between them and the 4 percent of children who were not physically disciplined.

The study found that 4 percent to 7 percent of parents fell into the "red zone" by disciplining their children frequently and impulsively, by such means as verbal punishment, using a paddle, hitting their children in the face or torso or throwing and shaking them.

Those children were found to be not as adjusted socially and more likely to have behavioral problems or experience anxiety or depression, Owens said.

She acknowledged that the children studied were from an earlier generation and the results could be different if the same research were done on today's youngsters.

A study released last August found that avoiding corporal punishment altogether increases the probability of the child being well-behaved and well-adjusted. Murray Straus, co-director of the University of New Hampshire Family Research Laboratory, said spanking could backfire and push a youngster into delinquency.

Others said that they are not sure what the overall effects of corporal punishment are, but that spankings can create mistrust between parents and children and send the wrong message to youngsters.

"I have a hard time imagining it would be a constructive part of the relationship," said Peter Mangione, co-director at the San Francisco-based Center for Child and Family Studies. "The child is learning from you that it's appropriate to use physical power to solve problems."

Owens, herself an expectant mother, said she is not advocating spanking, "and I don't plan to use it, but if there are situations where I think it would be helpful, I wouldn't be averse to using it" in a mild way.