To be a parent is to worry. From the earliest moments of utter helplessness, your heart is sworn to Protect This Child, and the love you feel is matched by terror at the thought of the many things that mustn't happen.

Many such things do happen in the film "Thirteen." Holly Hunter as single mom Melanie does everything right -- she's cool, fun, and loving, but also strict, not a sucker for that "best friend" trap; yet her daughter Tracy, so sweet at twelve, at thirteen is running wild in a kaleidoscope of drugs, petty crime, and fellatio with her bad-girl friend, Evie. The movie avoids making blanket statements, and there are plenty of kids in it you'd be proud to call your own (though not many with speaking parts). Still, it's unsparing in its portrayal of a scenario that's not even the worst possible. What is a parent to think?

At eight months, our son Bobby Dashiell is just starting to crawl. Watching him make his way across the wood floor with a spastic butterfly stroke, I'm struck by the urgency of his instinct to explore. According to the experts, it will be almost a year before the boy develops self-awareness -- the understanding that he exists in the world -- but already he's driven to cover every inch of the kitchen and put everything he finds in his mouth, shake it, bang it on the floor, raise it high in the air, and drop it before moving on to the next new experience.

Growing up is all about gaining sophistication. A child gathers information about people, places, and things, and learns new ways to think about them. But which information, and when, and how much? There are things you want your child to know -- that the cat is soft and returns gentle affection in kind; that his arms can be used to avert head bonks; that we're always nearby, even when he can't see us. There are other things that you wish he never had to learn about, like war and rape and racism. And there are many, many things he's likely to discover a lot sooner than you would have chosen.

Given the raw power of a child's curiosity, and the many ways the world stands ready to meet it, a parent could never hope to control a child's education; the most we can aspire to is to pace them breathlessly, as if running alongside a wobbly bicycle, and offer context and understanding for the things they're learning. As if we understood them ourselves.

This has never been easy, but has it become more difficult? On one hand, kids have been getting into trouble -- or not -- since time immemorial. On the other hand, have you looked around lately?

I want to make one thing perfectly clear. At 36, I may have passed beyond the chosen demographic, but I'm no old fart. I got my last tattoo just two years ago. I still annoy the neighbors with my stereo. I was going to Burning Man long before it got all theme park-y. Burning Man! Of course, back then we had to use a flint rock to get him lit.

But things have changed. When I was thirteen, American culture was all John Denver and the Muppets on the cover of Newsweek and Jimmy Carter in the White House, and the only media aimed at kids were Saturday morning cartoons, After School Specials, and Dynamite! magazine. Barely out of the Pong Age, video games were far too abstract to associate with actual violence or adult themes. MTV didn't come on the air until just after my fourteenth birthday, and when it did, staple videos by The Human League, A Flock of Seagulls, and ZZ Top were nothing you couldn't watch with your grandmother.

Sure, there were Farrah Fawcett posters and toy guns and glue-sniffing and knowing older siblings when I was a lad. I'm not going to pretend we spent our days singing doo-wop down at the fishing hole. But the media environment in this Too-Much-Information Age is far more intense and pervasive, and its impact inevitably greater, bombarding today's kids at every turn with a Clockwork Orange-like montage of sex, violence, and materialism. As they enter the hopeless awkwardness of puberty, they're hounded by images of idealized teens replete with fake boobs, washboard abs, piercings a-go-go, and oh-so-worldly attitudes about blow jobs. Video games are based on first-person mayhem with chilling realism, and if that's a little too intense for you, just go play with a doll instead, you big baby.

"Where are the parents?" That's what people always say when this topic comes up. There's no reason for filmmakers, game developers, and TV executives to exercise restraint or take responsibility for their potential influence of their productions on young minds. Mom and dad can simply spend their ample free time researching every new production that appears in every medium -- every game, movie, Website, TV show, clothing trend, music style -- and rating it either Okay or the No Way. And don't forget about your kids' friends -- what are the rules at their houses? What do you do if the parents hosting the sleepover have looser standards than yours -- humiliate your kid, or grin and bear it and hope for the best?

Parental savvy is all well and good, but you'd be a fool to get into a shooting war with the whole of youth culture. One thing that "Thirteen" makes painfully clear is that even the best parents in the world can't always be there when the crucial decisions are made. Nor should they expect to be -- the whole point of childrearing is to teach kids to make the right decision on their own in any situation that comes up. Just like every decision you make is the right one, every day of your life.

It's tempting to assume that bad or sad or otherwise messed-up kids are the result of poor parenting, but that would be too easy. Everyone knows a once-wonderful family brought down by a runaway or a drug casualty or suicide. Ultimately, it's largely a matter of luck.

Luck comes in many forms. One is making the right friends. Tracy had friends, but she outgrew them, or thought she did, at the worst possible time, right when things started getting complicated. Her little study buddies suddenly represented all the little-girl naiveté she sought desperately to shed, while Evie offered access to the big-girl world about which she was so curious. Will Bobby make that one fatal friendship, or will he find smart, well-adjusted companions with whom to make common cause against peer pressure?

Will his junior high schedule include that one special teacher who fosters a lifelong love of learning, or one of those sadistic fuckers who seemingly enter the profession to crush the spirit of their students?

When he weakens as a designated driver, will the streets be clear of tragic consequences?

When his hormones overcome his safe sex training, will his partner come with a clean bill of health?

Will he get a break when he should have known better, or will his future be defined by a single stupid mistake?

Will the interests and talents he develops as a child continue to flourish as he grows older, and provide a foundation for a rich and fulfilling life?

Bobby's future is almost too overwhelming to contemplate, except for one thing. I've been feeling lucky lately. I feel it when I go into his room in the morning and see him smiling at me from his crib. I feel it when he sings to himself in the stroller, and when he laughs at something only he has noticed. I feel it especially when he's going down for the night, all sleepy-eyed and limp, and he leans from his mother's arms to suck my nose one last time.

I'm hoping our luck holds.