Q. "I am a single mother rearing two sons, 10 and 14. The 14-year-old goes out on Friday and Saturday nights with some of his friends, who are 16. They either go to the movies or roller-skating, and then stop for a snack. What is an appropriate curfew for him at this age? Eleven o'clock seems reasonable to me, but he thinks he should be allowed to stay out later.

"Also, with summer coming on, I am concerned that he will want to be out late every evening. What is an appropriate curfew for summer evenings, since I have to get up for work in the morning?"

A. The very word "curfew" has a warlike ring to it: It draws such a line in the dust. The fewer challenges you can give to a teen-ager, the easier your job will be.

That's why a general hour usually works better than a flat curfew, unless the time has been extended for some special event. To ask your child to come in "between 10:30 and 11:30" -- according to his judgement -- would give him a greater sense of control of his life, and that's what he needs at his age.

Although your time seems about right at 14, it's hard to give an appropraite hour. What's right for one family isn't right for another.

Basically, it's his safety -- and your sleep -- that matters. When people live together, whether in a family or a bigger community, the concerns of each other must be balanced.

It's perfectly reasonable that you would worry if he were out later than a certain hour and that you need 8 hours of sleep, especially if you have to work the next day.

And when he says he won't wake you -- and he'll say it -- he should know that you can sleep only lightly until he gets home, and then you want to talk with him a few minutes, hear about his good time, kiss him goodnight. While he'll know this is a time-tested way for a mother to make sure her child is in good shape, he'll also know he's cared for.

Your child, on the other hand, will want to stay our as late as the other kids and that's reasonable too -- or it would be if the other kids were 14. The troubling part of your letter is not his curfew, but his company. While boys of 16 sometimes date girls of 14, they usually don't invite boys so young to join their crowd. The spread is much greater now than it will be between 16 and 18, when the ages meld better.

Boys of 16 (like boys of 18) are more likely to use pot and alcohol than at 14 and to drive cars, although they're not experienced enough to drive very well. This sets up the potential for trouble, and the later they stay out, the more trouble there may be.

It's that empty time that must bother you, and it should. If your son already has gone to a movie and had a snack, what else is left to do?

This may be the time for him to ask himself if the group ever does anything after his curfew that he wouldn't want to read about on the front page of the paper. It just might get there -- perhaps as a statistic.

According to the latest figures (1979), nearly 19,000 people between 15 and 24 were killed in all kinds of crashes -- from motor bike to automobile -- and a teen-ager was driving about a fifth of the time. Moreover, half of the fatalities involved a drinking driver (or two) and at least 11 out of 100 drivers were using some other drug. This is probably why the fatalities almost double between midnight and 2 a.m. on Friday and Saturday nights.

When a drunk driver crosses the center line it hardly matters whether your son is with a driver who has been drinking or not.

If your child feels that your concern is for his safety -- rather than your need to be proper or autocratic -- he will go along with you better. There still will be some challenges, some infractions, some experiments, but not as many or as often or as angry.

Bedtimes, allowances and curfews are meant to be raised, but within the framework of the family and responsibility -- and age -- of the child.

If your son's 16-year-old friends are such good friends, they will understand if he has to go home a little earlier than they do. After all, they were young once too.

Q. "You recently wrote about a 21-month-old child who was getting rebellious. The parent may be interested in a six-page newsletter called Growing Child. You send in your child's birthdate and get advice that fits his own age, month by month."

A. You're right. It's a good publication and a welcome one, with 72 issues from birth to 6. To get a year's worth of advice, send $11.95 (with the birthdate to 22 N. Second St., Lafayette, Ind. 47902. You also will get a newsletter of ideas called Growing Parent and a catalog of age-dated books, records and educational toys, which are sent monthly too.