WITH MOST of America's children now firmly back in the arms of their schools, the parental sigh can be heard from coast to coast: Finally. No more scrambling for sitters, taking extra time off work, or laboring over a daisy chain of day camps. ''It's the most wonderful time of the year," sings the blissed-out dad in a popular advertisement for back-to-school products -- and many parents heartily, if also a little guiltily agree.
We have lived for a long time now in this world where parents and children spend many of their waking hours apart. Thus the particulars driving family-child separation in all its varieties -- daycare, before- and after-school care, dual income parents, single parents, divorce, illegitimacy, smaller family size -- are more than mere sociological facts of life. They are also changes that have left grownups freer and financially better off than before.
So it is practically unheard-of now to ask this blunt question: What, if anything, is this kind of chronic separation from family doing to kids? And yet empirical evidence abounds that at least some of the problems unique to this generation share this common denominator: Many kids today spend too little time with protective, loving adults and other family members, and they are worse off because of it.
Consider this example from current headlines: childhood obesity. Also familiar is the current explanation for all this, which fingers an institutional culprit: ''big food" with its refined sugars, seductive advertising, gargantuan portions, and pernicious vending machines.
Yet common sense fairly shouts that while big food might explain the ''how" of kids getting fat, it cannot possibly explain the ''why." In other words, why are kids allowed to sit around and do all this unsupervised or parent-subsidized eating in the first place? The answer is both obvious and unwelcome: because broad changes in the way children now live often mean that no one is around to tell them to stop gorging themselves.
After all, why were baby boomer kids so much more svelte than their own children? Because most baby boomers came from intact families with someone in the home after school -- typically an adult someone who could tell them to get out of the cupboard, wait until dinner, or go outside and play. Today's children typically spend those after-school hours very differently -- in programs where sugary high-calorie treats abound or in empty homes with ready access to bulging cupboards and refrigerators. Those same empty homes also mean that in many neighborhoods not enough adults and other kids are around any more to establish the social ''safety net" necessary for outside play. The wonder in such a world is not that many kids are heavier than their parents were. The miracle would be if they were not.
The connection between absent family and juvenile trouble is also glaring in the case of another health problem: the epidemic of sexually transmitted diseases. Here again, adults point elsewhere -- say, toward the ''good news" about teen sex in the form of lower pregnancy rates. Yet that good news does not change the fact that millions of young people are already infected with diseases that will give some of them, notably the girls, serious problems with fertility and complications including cancer. One recent study in Chicago confirmed what others have concluded: Today's kids are more likely to have sex in a home setting, meaning their own or someone else's. Who needs to go out of their way for a back seat, when someone's (adult-empty) home is so much more comfortable and accessible?
There is also evidence that many kids today are worse off both emotionally and behaviorally than the generations before them. Consider the sharp rise these last couple of decades in diagnoses of psychiatric problems in juveniles and the concomitant explosion of psychotropic drugs used to treat these disorders. Here again, however, the argument that ''we are just better at diagnosing these problems" cannot possibly explain the steep rise in diagnoses and medication over the past generation.
Obviously, something else is going on when millions of kids are being diagnosed with behavioral and mental problems in the first place. Perhaps that thing is the obvious thing -- that many children are behaving worse not because of hard-wired ''brain defects," but because they are feeling worse in their long, institutionalized, separated days.
Because we are reluctant to face the evidence that too much familial absence causes harm, the adult world has instead become a collective excuse factory, pointing the finger for juvenile problems anywhere but at ourselves. There's a word for that: denial. Before breaking out the apple juice on back-to-school night, it's worth stopping to wonder whether a little less of it might leave at least some kids a little better off.
Mary Eberstadt, a research fellow at Stanford University's Hoover Institution, is author of ''Home-Alone America: Why Today's Kids Are Overmedicated, Overweight, and More Troubled Than Before."