This depends entirely on the resources of the parents. Time, money, ability to be emotionally close and available to their children, and physical energy. One aspect is no more or less important than the other. If you aren’t able to check all the boxes, then it is wise to limit the number of children you have. It is about fairness to the kids. I have known many big families, and grew up in one, also. Some were happy and healthy. Others weren’t at all. I came to the conclusion some people are cut out for it, and others aren’t. One final thing to mention is if the parents are extroverts and desire a big family, they should remember some of the children they bring into the world may be naturally introverted. Set your family up in a way that it respects this difference. Life is often miserable for someone who is introverted and is forced into the chaos of a large family. And large families are chaotic by their very nature…good chaos is possible, but it is still chaos nonetheless.