I don't have studies, no. Just going by personal experience. Sorry that isn't good enough.
As for assumptions, why do YOU assume that these kids couldn't possibly be happy, well-adjusted, intelligent kids?
I never said you were against homeschooling...just that it does mean they spend far more time with their parents than the average kids. Yes, there are lots of them...but in my own experience, I was always able to talk to Mom about anything and everything - which equals "quality time" in my book.
I'm sorry, but immediate disdain for large families and sarcastic, pitying remarks about the pooooor children get my goat, and I feely admit to being overly sensitive on the subject. I've heard my share of "you know what causes that, right?" kind of statements in my time - people just couldn't get it through their heads that people might actually WANT a big family, and that the actual KIDS enjoyed having a big family.