His children are growing up. This is not exactly a news bulletin, he tells the woman on the bench next to him. It's what children do. It's their thing.

Still, he says, facing the baseball diamond, he thought this growing up would all be gradual. Instead, his kids seem to lurch from one age to the next, the way the oldest takes the corner in his driving lessons. They shift from one gear to the next with the most unnerving sound effects.

He remembers when his eldest was only three. The nursery school boy holding his hand said hello to someone on the street. How could the boy know someone the father didn't know? Even then, he felt these tiny electric shocks of independence.

Now they were going through rites of passage again. The oldest is getting his license. The youngest is heading for junior high school.

On cue, the 13-year-old came up to bat. In a matter of weeks, months, the boy had gotten it together: the wrists, the stance, the eye. It was as if his body had been preparing for today's final exam. He passed it with a solid double.

The father watched him as only parents watch their own. Too proud one minute and too critical the next. To be a parent is to know excess. But today, he felt something else, between wonder and wistfulness, between love and loss.

Maybe, he says to the woman, he is going through a kind of adolescence himself. Maybe parents go through a second one with their kids: caught here between the pleasure of seeing them grow and the pain of letting them go.

He chronicles the little things. The projects they bring home from school have changed. A butcher-block table replaces the first raw wooden-block candlestick. A 16-page civics paper replaces the crayons. The boy heading off for camp once had anxiety; now he has a list and extra socks.

While they talk and watch, the teams change sides. The 13-year-old swoops by to pick up a glove and heads for third base. Someone hits a line drive at him and the boy drops it.

The father is on his feet in a second and then back down again. He tells the woman: two years ago, the boy would have been in tears; now he recovers quickly. The woman tells him: two years ago, you would have been compulsively coaching; now you are a spectator.

Yes, he says, we are both growing up. But, he adds grumpily, the difference between my son and me is that I have been his age and he has never been mine. The two laugh. This is a difference that makes no difference.

Yes, once upon a time, this man thought he knew a great deal about fathering. He had, after all, been a child, had a father. He pictured himself, guiding his children around the potholes of his own youth. He would pour everything he had learned about life into their heads so they would be protected from the worst.

He thought his life would be a foundation that they would build on from where he left off, like skyscrapers.

But his children are more like he had been than like he wished he had been.

Now, gradually, he was beginning to accept what Doris Lessing once wrote, that "his son, all of them would have to make the identical journey he and his contemporaries had made, to learn lessons, exactly as if they had never been learned before."

In turn, he was learning the lessons his father had learned before him: about the intensity of feeling and wanting for his children, about the need for letting go.

The game ended. The lanky younger son loped over. He handed the 42-year-old man a glove and a ball. He took $3 to buy pizza with the team and took off. Halfway across the field, the boy yelled, "Hey, day, thanks for coming."

The man waved after him. It was okay. It was what happens. They grow up.