FAMILY LIFE : On Their Own : At what age is it all right to begin leaving a child home alone? It’s a touchy subject for most parents.

In last year’s movie “Home Alone,” seemingly responsible parents accidentally leave their 8-year-old son behind when they rush off on a Christmas vacation in France.

In this year’s sequel, these same caring parents do it again. This time they lose track of their son at the airport and he ends up on his own in New York City.

You might say it’s the stuff of movies. But then along comes a shocking real life “Home Alone” situation, which occurred last month. A Chicago-area couple was arrested for leaving their two daughters, ages 9 and 4, home alone for several days while they went on an Acapulco vacation over Christmas.

Of course, you’d NEVER do that, you say. You might leave your child alone for 15 minutes, an hour, after school or in the evenings. But never for days.

But then the question arises: At what age is it all right to begin leaving a child home alone for short periods of time?

It’s a touchy subject, and one all parents probably grapple with at some time. Making things tougher, experts say there is no magical age when a child can safely be left alone. It’s an individual thing, they add, different with every kid.

“There are so many factors to consider--the maturity level, intelligence, siblings, sensitivity to fears, impulsiveness, hyperactivity,” said Tom Prinz, a Ventura psychologist who has written a book on parenting called “Dragon Slaying for Parents.”

All things considered, Prinz said 8 or 9 years old is the earliest a child should be left home alone. But whatever the age, he suggested that parents begin slowly, leaving for 15 minutes and gradually lengthening the time.

“The analogy I use in parenting classes is that it’s like flying a kite,” he said. Letting out too much string won’t work, he explained, nor will holding the string too tightly. “But it’s hard to know just how much string to let out.”

Prinz said he believes it’s as important for children to have time alone and develop a sense of independence as it is for parents to have an occasional break from their children.

“If parents never let their kids spend time alone, then that’s not healthy,” he said.

Kathleen Smith, a Simi Valley-based psychiatric social worker for the county’s Mental Health Services, takes a more conservative approach.

Even for short periods, she said, it’s better to wait until a child is 10, and then it depends on the maturity level of the child. Before parents begin, she advised, they should ask themselves whether their child can be trusted to follow rules in their absence.

Working parents face the added dilemma of deciding when a child is too old for after-school day care and is ready to handle being home alone until the parents return.

Many parents take this leap when their child starts middle school. Smith, however, recommended waiting until a child is in high school. But if that’s not possible--perhaps because the parents can’t afford child care--she acknowledged that it is sometimes unavoidable having to begin much earlier, sometimes even at the elementary school level.

California law doesn’t address at what age a child legally can be left home alone, according to Sally Allen, program manager for the county’s Children’s Services Division. And for parents, the guidelines make it a kind of Catch-22 situation.

“You can do it unless something happens,” Allen said. “As long as it works, it’s OK.”

Like psychologist Prinz, Allen advised against leaving a child alone, even for a few minutes, before the age of 8. Even then, she said, 8 is “borderline.”

Smith’s perspective comes from knowing what can happen if a child is not ready to be left on his own. In cases when things have gone wrong, her agency is called in to check things out. Situations have ranged from a child who has locked himself out of the house, to a child who has started a fire by cooking on the stove.

Deciding what steps to take--and whether the parents were negligent--is based on many factors, she said.

“We don’t remove children if it’s a fluky thing,” Allen said. What the agency looks closely at is whether the parents took all the right steps to prepare the child before leaving him home alone.

Those steps, child experts say, are as important as the factors taken into consideration before deciding to leave a child alone. Here are some of the most important precautions:

* Make sure the child knows how to use the telephone to call 911. Children should know where their parents are and have their telephone numbers handy. They should also have the telephone numbers of one or two neighbors to call if their parents cannot be reached.

* Children should be advised to keep the door locked and admit no strangers, but they should know how the lock works. Parents should set rules on whether friends can visit. (Most parents don’t want their child visiting another child who is not being supervised.)

* Latchkey children should check in with a parent by phone as soon as they arrive home.

* Children should be warned not to use the stove and parents should be clear about which appliances they may use (the television, VCR, etc.).

* If children answer the telephone, they should be cautioned not to reveal that they are alone to a stranger. Fibbing is OK in this case. Children can say the parent is busy and that they will take a message.

Parents can be creative when they believe their children are ready to be left home alone, said Corbett Phibbs, a family therapist at Parenting Plus in Newbury Park.

One mother that Phibbs knows doesn’t want her son to answer the telephone while she is gone, so she uses a signal if she needs to call him: She lets it ring twice, then hangs up and calls again. Car phones and beepers also make it easier for parents to be instantly in contact with their child.

Phibbs recommended that parents grappling with the dilemma of whether their child is ready to be left alone should ask themselves an important question: What’s in the best interest of the child?

“It may be good for the child to have the responsibility of being alone, of having the experience of being trusted,” he said. But he added that parents also owe it to their children to provide a “safety net,” one that includes a network of friends and neighbors who would be available to help the child if it became necessary.