Children often choose not to eat meat, and must be taught, or forced, to eat it. In fact, a quick perusal of parenting books and websites makes it clear that one of the most common food-related issues that parents have is the problem of making their children eat meat. Parenting "experts" treat this "problem" as one of children being picky or going through a phase, and parents are encouraged to model "proper" behavior or to disguise the meat in other kinds of foods in order to get their kids to learn to enjoy it. The question, then, is how many children are making a moral choice to abstain from eating meat?
For the most part, scholars have questioned whether children as young as Luiz even have the cognitive skills to make a moral statement like Luiz makes in the video: "When we eat animals, they die!...I don't like that they die." But a 2009 study by Karen M. Hussar and Paul L. Harris (Children Who Choose Not to Eat Meat: A Study of Early Moral Decision-making) showed that very young children like Luiz do in fact stop eating meat for moral reasons. In other words, it's not that they are picky or going through a phase. They, or at least some of them, have made a conscious choice on moral grounds.
One has to wonder how many children, if they had parents who did not cajole, manipulate, or force them into eating meat, would end up as vegetarians?