You won't have any trouble finding sources of more information. There are Web sites like www.vegetarianteen.com and www.vrg.org., and plenty of books. The one Aislinn gave me when she made her pitch was Vegetables Rock!: A Complete Guide for Teenage Vegetarians by Stephanie Pierson (Bantam, 1999). Written by the mother of a vegetarian, it is readable, useful, and even has some pretty good recipes.

The next step is coming to agreement on what kind of vegetarian your kid will be. Aislinn made it easy. She went for lacto-ovo-vegetarianism; she eats eggs and dairy besides plant foods. Vegans, who eat only plant foods, have to work a lot harder to get all the things growing bodies need.

At first, Aislinn even agreed to include shellfish - something quote-unquote real vegetarians would call cheating. It soon become a moot point. While vacationing on Cape Cod, we spent a morning clamming and then whipped up some linguine with white clam sauce she'd wolfed down the summer before. A couple of minutes into dinner, I noticed her fork was moving the bits of clam in various directions around her plate, but none were making it to her mouth.

"You're not going to eat that, are you?" I asked.

"I feel bad for the clams," she said.

I tried to make the case that clams fell well below the food-with-a-face radar, but that didn't cut it with my principled daughter. The rest of the family ate a lot of white clam sauce the next couple of days.

(Strict vegetarians might not approve, but Blatner, a registered dietitian, said she's seeing interest in the more relaxed versions of vegetarianism, including "flexitarians." They're vegetarian most of the time, but will occasionally eat animal foods.)

Once you get the ground rules down, you can move on to the preparation of food. A vegetarian diet can be very healthful, but not if it's mostly pizza, chips and sweets. Stock up on stuff like fruits, crunchy vegetables, low-fat cheese, nuts, whole-grain snacks and yogurt, if you don't already.

On to the real challenge. I repeat: You do not want to prepare two completely separate dinners every night. Adolescence is enough to put up with; you don't need to feel like you're running a restaurant out of your kitchen.

The way we get around this most nights is pretty simple. Either we make a vegetarian entree everybody will eat and round it out with a salad and good bread. Or we make a vegetarian entree and use it as a side dish for non-veggie family members.

For example, early on we found a great recipe for anchovy-less puttanesca sauce that everybody loves. Those nights, no one misses meat. Check out the accompanying recipe.

Some weeks, we make a couple of pots of different bean dishes to freeze in individual portions.

Cuban black beans come to mind. Aislinn has them over rice. Everybody else will have a smaller portion with whatever meat and vegetable we're having (see accompanying recipe).

Well-spiced, stewy bean dishes are great to have on hand. A lot of kids love to make their own tacos. Whip up some seasoned ground meat, and thaw and heat beans for your vegetarian. Aislinn's little sisters like the beans so much they eat them along with the beef.

As with any new kind of cooking, part of the challenge is hunting down recipes. There are some great vegetarian cookbooks out there. We owe former White Dog Cafe chef Aliza Green big time for her volume The Bean Bible (Running Press, 2000). It's not a vegetarian cookbook, but it has many wonderful no-meat recipes that everybody in my house loves.

Two recent cookbooks had several recipes that struck our resident vegetarian's fancy.

Pure Vegetarian (Kyle Books, 2006) by Paul Gaylor is for foodie home cooks with recipes like vegetarian pho and steamed Asian buns. Quick-Fix Vegetarian (Andrews McMeel Publishing, 2007) by Robin Robertson features dishes that take 30 minutes or less to make, like Thai noodle salad with peanut sauce and potato dosadillas. (See accompanying recipe.)

Of course, you needn't start a new cookbook library. Many of the world's cuisines have great meatless dishes found in ethnic cookbooks you already own.

Then there's the actual cooking. Any kid who can advance a convincing case for becoming a vegetarian is old enough to help with the cooking. Aislinn helps with prep work, and there are dishes she does solo quite nicely. She does a decent omelet, she's made pasta for herself and her sisters more than once, and I have a soft spot for her Caesar salad.