Let's hear it, what differences?
Well, I don't like to generalize, as I have not seen every 40-something parent, but it seems to me that a lot of the 40-something parents that have kids my kids' age don't spend half as much time being involved in their kids lives, from volunteering at the school, or clubs or sports. They also seem to be more apt to have a child who has behavioral problems, as they don't seem to have the stomach to enforce limits or follow good discipline suggestions. They are more inclined to find care outside of the home for their kids, not that there is necessarily anything wrong with that, but I've seen enough cases where I can generally tell which kids spent their early childhood in daycare, and which ones had some sort of family care provider.
But like I said, I have not seen every boomer parent, just the ones who have kids that are the same age as my kids.