According to the American Dietetic Association:
Well-planned vegan and other types of vegetarian diets are appropriate for all stages of the life cycle including during pregnancy, lactation, infancy, childhood, and adolescence. Vegetarian diets offer a number of nutritional benefits including lower levels of saturated fat, cholesterol and animal protein as well as higher levels of carbohydrates, fiber, magnesium, potassium, folate, antioxidants such as vitamins C and E and phytochemicals. Vegetarians have been reported to have lower body mass index than non-vegetarians, as well as lower rates of death from ischemic heart disease, lower blood cholesterol levels, lower blood pressure, lower rates of hypertension, Type 2 diabetes and prostate and colon cancer.
—American Dietetic Association position
paper on vegetarian and vegan diets.
In the seventh edition of Dr. Benjamin Spock's Baby and Child Care—the last edition published during Dr. Spock's lifetime—he spelled out some good advice for children's diets. He recommended that children be served plant-based diets—vegan diets—and that, to deal with finicky eaters, the best approach was not to arm-wrestle with children but rather to simply find healthful foods they will eat. For example, children may not like cooked spinach, but they might like fresh spinach as part of a salad. They often are not keen on more exotic vegetables, but they are fine with corn, carrots, green beans, etc. Virtually all children like the following:
Legumes: baked beans (okay to add cut-up veggie hot dogs), lentil soup, split pea soup, peas, bean burritos, bean tacos
Vegetables: carrots, green beans, vegetable soup, salads
Grains: rice, whole grain bread, oatmeal, cold cereals with soy milk or rice milk, corn, vegan pizza, spaghetti with chunky tomato sauce
Fruits: apples, bananas and all others
Meat analogues: veggie burgers, veggie hot dogs, etc. (Soy-based ones have a cancer-preventing effect for girls and are healthful for all children.)
It is also important to provide a pediatric multivitamin. PCRM has a book called Healthy Eating for Life: For Children, which is very detailed on veganism and kids.