Earlier quoted context omitted.
Amusingly, both my mom and her sister had 3 children because their parents had 2. They were annoyed because one of them was "daddy's child" and one was "mommy's child" and they figured that having 3 each would prevent that. Numerology matters. They both did end up having 3 kids, and I can report that I think the problem they thought they were preventing didn't happen. Win!
Can you describe the dynamics that did occur? Were the kids happier overall when there were 3 of them than 2? I know it’s tough to reduce everything to that one factor but still curious.
Yes, that's the whole problem with this discusion. It isn't scientific, lots of anecdata, and correlation does not imply causation.