Keeping children healthy and well nourished on a vegan or vegetarian diet is a daunting although do-able task.
Although basically against raising children without any foods at all from animal sources, I respect the beliefs of those who, for ethical or religious reasons, decide to do so. If that's you, I beg you: be sure you are well informed and well advised. I've seen too many unhealthy-looking, anemic kids from well-meaning parents who decided to go that route. Sometimes teenagers decide to go vegan or vegetarian, either from some belief or out of rebellion. Then we have a task ahead of us to help them eat well enough to nourish their developing bodies.
Also see the article that asks "Taking Care of Dem Bones?"