My friends who have children are all getting sucked dry by them, whatever their income level. It seems like those who make a lot more money do things like send their kids to private schools. And most of the couples I know with kids have one person who is underemployed. I know more than one person who pretty much breaks even working after factoring in day care, but they just want to stay employed. (Or staying home with Junior is not as engaging as working -- many parents have told me that.
I don't mean this as a slam against having kids at all, but I have noticed that this decision has very much impacted me financially. Most people I know who have carefully considered whether to have children (as I did, years ago) have given economics some consideration, but the cost of kids is vastly underestimated.