I have two of them -- one on the cusp of 13, the other, 16. I love them dearly and they love me, usually.

The most important thing to know is that teenage boys are like clamshells. They open up just for a moment, in order to take in a little nourishment or expel some dirt. But then they clam up tight again.

If you’re around when they open up, you have a chance to see something truly beautiful inside. Maybe a small pearl turning into a gleaming stone. Maybe a shiny-smooth inside, still vulnerable. And you have a quick chance to connect.

But you have to be there in the moment. The clam shuts in an instant, and then you can’t see or do a thing.

Forget what you’ve heard about "quality time." Teenage boys don’t want it, can’t use it, have better things to do. When I came home from Bill Clinton’s cabinet and suddenly had weekend time to spare, I waited for one of my boys to take me up on my offer of hours of quality time with them. "Sorry Dad. I’d really like to go to the game with you, but .. Well, you see, David and Jim and I are gonna hang out in the Square." "That’s a cool movie, Dad, but ... well, to tell the truth, I’d rather see it with Diane."

I suggested we make a plan, mark our calendars. But when the time came, there was always someone or something else. Teenage boys can’t be scheduled.

But a few weeks ago, around 10 p.m., when I was just beginning to fantasize about going to bed at a decent hour, one of them wanders into the kitchen. "Can you listen to me practice my debate, Dad? The competition is tomorrow. I need your advice."

My advice? He wants my advice! I try to hide my glee. "Sure," I say calmly. I’m afraid if I conveyed my tidal wave of enthusiasm the clam would shut tight against the surge.

I listen to him for the full five minutes. It’s terrific, and I tell him so. He smiles bashfully.

"Any criticisms?" he asks. "Must be something I can improve on."

"Well, I suppose you could speak more slowly at the start," I say, oblivious to the dangerous currents. "And try to give your main argument a little bit more emphasis, like this..."

I plunge in, clothes and all. I repeat part of his argument, but with dramatic flair. I add a few points he hadn’t thought of. I entertain the imaginary audience with witty asides, silence them with bold logic, charm them with clever examples.

Out of the corner of my eye I see the shell closing. It’s too late. All he had wanted was a little advice, a helpful hint. He didn’t want his dad to take control. He merely wanted his dad on his side in this competition. He didn’t want to feel competition with his father.

"Thanks, Dad," he says in a tight voice. He leaves the room. I feel like a fool.

That’s the other thing to keep in mind. Sure, you have to be there when the shell opens. But you can’t be too much there, or it will close on you even before you’ve had a look inside.

Teenage sons know they will have to make their own way in a few years. They create a shell so they can have some privacy, so they can find out what it’s like to be alone in the world without actually being alone in the world. They’re testing the waters. They open when they need a little advice or reassurance or love, which are really the same thing. You have to give it to them, but not too much of it, or else they can’t do what they have to do.

A father is hard for a teenage boy, I think, because the father has already made it out there in the salty brine, and the teenage boy isn’t at all sure he can do it. The father is a constant reminder of the challenge ahead. The shell protects the boy from the fear and the pain of what he has to do, and it also protects the father from all the anger and resentment inside the shell about having to do it. "I want to grow up to be just like you! But I don’t want to grow up, and if I do you’re the last person I want to be like."

I remember. Don’t you?

Now I content myself driving them to their friends’, and to tennis matches and debates and drum lessons. These moments in the car are quiet, private, unscheduled. Sometimes the clamshells open. When they do, I listen, trying not to be judgmental or to take control or to say too much. We joke about all sorts of things.

Usually I drop them off a few blocks from where they’re heading. It wouldn’t be cool to be seen being driven by your dad. Teenagers pretend to one another that they don’t exist within families. They pretend they’re already at sea.

It’s hard being a teenage boy and having a father. But I imagine it’s much harder to be a teenage boy and not have one.

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