Three is too many. ;)
Heh, just kidding.I have an older sister and a younger brother, sooo....
Anyway, I think it depends on what you can afford. If you can financially provide for 6 kids, have up to 6 kids. If you can't afford them, I think you're being a little unfair to the children , yourself, and the rest of your family.
I hate to conflate money, with love, and children, but we do live in a reality based universe and not a Disney fairy tale. If you have a cramped one bedroom apartment you can barely afford, AND you have one or two children, should you really be looking to get a 3rd? Or even risking it?
Just my opinion, which apparently isn't even worth 2 cents on an upvote! lol