Calm down. You haven't turned your kid into a monster by sending him or her to the day-care center so that you can hold a full-time job.

Yes, the news announced at a conference last week on child development sounded a bit alarming. A group of researchers reported that 4½-year-olds who had spent a lot of time in day-care centers were somewhat more aggressive than those who had spent that time at home with their moms.

This report needs to be put into perspective. Though the study, sponsored by the National Institute of Child Health and Human Development, was large and well-designed, its results were anything but clear. Inconsistencies abound in the data: "statistically significant" differences found at one age were not found at another; mothers' judgments didn't agree with those of other caregivers. Some findings held true for all kinds of nonmaternal care; others were true only for kids who spent the time in day-care centers. No wonder the various researchers involved in this study seem to have different interpretations of what they found. No wonder it has taken them so long to report their results. (The kids in this study are now 9 or 10 years old, and we're just hearing about the data collected when they were 4½.)

Another drawback is that this was a correlational study, which means it can't distinguish causes from effects. Children who spend a lot of time in day care may be somewhat more aggressive at age 4½, but that doesn't prove that day care caused them to be more aggressive. It might be that parents who have rambunctious children are more likely to feel that they need time away from them, or that their children need opportunities to let off steam.

Even if the children's aggressiveness was indeed an effect, rather than a cause, of spending a lot of time at a day-care center, the increase in aggressiveness was too small to be alarming. For the most part, the children's behavior was within the normal range. Day care hadn't turned them into monsters.

What, if anything, had it done? Perhaps what it did was to give them more experience in dealing with their peers. Another way of looking at these results is that the experienced children were less likely to allow themselves to be pushed around.

We don't want our kids to be wimps. On the other hand, we don't want them turning into bullies. Are children who spend time in day-care centers more likely to turn into bullies?

Though it's too soon to be sure, my guess would be no. Over time, I would expect the children who hadn't gone to day care to catch up with their more experienced peers and learn how to stand up for their rights. There are already signs in the study's data that this is happening: The difference in aggressiveness was smaller at kindergarten age than at 4½. Perhaps in another year or two the difference will have disappeared completely. A 1992 Swedish study (reported in the journal Child Development) followed children to the age of 13 and found no adverse effects of early day care. In fact, the children who spent more time in day care in their early years were, at age 13, socially more competent and making better grades in school.

That last result--better grades--is consistent with a finding from the new study that almost got lost amid all the fuss about aggressiveness. The children who had gone to high-quality day-care centers were somewhat more advanced in cognitive skills than those who stayed at home with their moms.

Rather than seeing the day-care center as a potential hazard for children, we should see it as a potential opportunity. There are some things that children can learn best in the company of their peers, and one of them is how to get along with their peers. Educational programs designed for older children are sometimes successful in reducing bullying on school playgrounds. These programs are administered by teachers to groups of children; they succeed by making the group as a whole less accepting of aggressive behavior.

Perhaps the study's researchers would make better use of their time by devoting it to developing anti-bullying programs for children of preschool age.