Some infants who are shy or fearful may be born that way and this characteristic may persist through childhood and adolescence, a Harvard University researcher suggests.

Dr. Jerome Kagan says that recent research with children pinpoints shyness as one of the "more permanent" temperamental qualities.

In a study of 2-year-olds, he found more than 10 percent to be "very inhibited" and more than one-third of them appeared to be "biologically predisposed," either through inheritance or stresses on the mother during pregnancy, to this extreme shyness.

Although many children go through a shy period during the first year or so, Kagan said yesterday that in the children he studied the most inhibited ones often persisted at age 2 and beyond to be shy of visitors and eager to stay close to their mothers.

Over one-third of the inhibited children later became "less fearful." But those children who may have been born with a tendency toward this trait were less likely to grow out of it, he said in a presentation at the American Association for the Advancement of Science meeting here.

These children were identified as having higher and more stable heart rates while looking at pictures or listening to something that was unfamiliar or difficult to understand. Kagan interpreted this as a "greater effort to understand the familiar."

This group of children has been followed thus far to the age of 3 1/2 years and will continue to be studied when they go to school, he said.

He noted that other studies have shown that identical twins are "more similar in their tendency to be shy or outgoing" than fraternal twins.

That tendency might be inherited or could result, he suggested, from prenatal influences in the womb due to physical or psychological stress in the mother. The nervous system begins development, he said, in the fifth or sixth week after conception. Kagan cited another long-term study that he conducted in which a group of children was followed from birth to adulthood. He found that a small group--seven boys out of 36--who were "extremely inhibited and shy during the first three years of life" continued to be different throughout childhood and adolescence.

As adults, he said, they "chose less traditional masculine vocations" and were less likely to be good at things such as athletics. Because "this is the only evidence I know of that implies continuity of this temperamental disposition from infancy through adulthood, it should be viewed with some caution," he emphasized.

Another researcher at the AAAS session, Stephen J. Suomi of the University of Wisconsin, also presented data on monkeys suggesting that some may be genetically predisposed toward being "uptight" or "fearful."