Q: It is 10 p.m. as I type this. My 3-year-old daughter just fell asleep. She used to sleep 12 hours a night, from 7 to 7, but she hasn't done that in several months. I tried moving her bedtime to 7:30 and then to 8, but that didn't help. Every night, I take her blankie and sleep doll so she has nothing to play with, but she just lies there and sings and talks to herself. She shares a room with her 6-month-old brother and wakes him repeatedly during the two or three hours it takes for her to fall asleep. We tried spanking, but that didn't faze her. Taking away toys and privileges doesn't work, either. The only good news is she doesn't come out of her room. Help!!!

A: You're fighting a losing battle. This particular battle, in fact, is one of three battles you cannot win, no matter what. You cannot make a child eat, use the toilet or sleep. You can put a child to bed, and you can enforce staying in the room, if not the bed, but you cannot make the child go to sleep.

You've created a power struggle out of this issue, and it is axiomatic that when parents enter into power struggles with children, problems always get worse. I'd venture to guess that at this point in the struggle, your daughter is making herself stay awake in large part because she knows you want her to sleep. This is an example of what I call "parenting physics": Any attempt by parents to force what cannot be forced, to control what cannot be controlled, will result in an equal and opposite reaction from a child.

Accept that you've lost. Give it up. Surrender. Only then can you begin to solve the problem. Here's how: First, put your infant to bed in some other area of the home, at least temporarily, even if that means moving his crib into your room. Then, put your daughter to bed when you want her to be in bed. If that's 7 p.m., then 7 it is. (By the way, folks, keeping a child up late in hopes she will be more tired when she goes to bed increases the chance of the child becoming overtired, and overtired kids have great difficulty falling asleep.) Tuck her in, kiss her good night, wish her sweet dreams, leave her room, and let her take her sweet time getting to sleep. If you stop fighting with her and just let this issue alone, I predict that within a couple of weeks, maybe three, she will be falling asleep within an hour of being put down.

Q: My 2-year-old has a bad habit of tipping over a regular cup at meals. He will take a drink and then just dump the rest on to the tray of his highchair. We have tried only giving him a drink when he asks, only putting a small amount of liquid in the cup at one time, and taking the cup away and not letting him have any more. None of that has helped. He will still do this almost every meal. I have tried to not make a big deal out of it and just wipe it up or make him wipe it up but he persists. Any advice you have would be great.

A: I am convinced that many, if not all, mealtime problems today's parents experience with toddlers are due to the nouveau practice of having infants and toddlers join the family for meals. This does nothing but provide them with an audience for their typical shenanigans. It also causes meals to be tense experiences for parents and older siblings. As recently as the 1950s, very young children were fed separately, before the rest of the family sat down to eat. In my case, for example, I didn't eat with the adults until I was at least 4, and I didn't suffer. I preferred it, in fact. I believe in feeding infants and toddlers first, and then having the rest of the family sit down to the meals while the little savage is allowed to run around doing his/her "own thing." When the highchair has served its purpose, buy a toddler-size table and chairs and put an absorbent pad under the table (these can be purchased at pet supply stores). Give your son very little liquid in the cup (no more than a couple of tablespoons) and let him have his fun. When he discovers he's no longer getting a reaction from you, this too will pass.

Family psychologist John Rosemond answers parents' questions at www.rosemond.com.