And to counter yesterday's rant, let me chat about something I've sen done really well. I am super picky about kids in books. Perhaps I like kids too much to see them used as plot pawns or just got sick of the precious little children who appeared long enough to ask, "Will you marry my daddy?" or some such ridiculousness.
This is by no means a comprehensive list but tome people I have seen do kids really well include:
Lani Diane Rich
Sandra Kitt (who has more than one teenager in For All We Know
Now you might notice I have not included young adult or children's authors, and it's not that I think they are unworthy, it's that I think that's a whole different skill, creating a believable protagonist who is also a kid or young adult.
(Also, that list is really, really long for me. This one probably would be too if I really sat and thought about it.)
*Nora Roberts even has kids who start big life conversations with their parent's love interest, but they do it in a way that sounds like a real kid, rather than a scripted kid.