Care, feeding and education of. They have been my largest single expense since they were born. Fortunately I can think I am starting to see the light at the end of the tunnel as their undergraduate courses are nearly finished.
Yeah I can't imagine how they could possibly have left that one out. Tiny babies are very cheap to look after but it's all downhill from there.
Our kids attend a Catholic school, so there are obviously discounts for multiple kids (3 in primary school, one in high school), but it's still fairly expensive.
And 3 of them (and my wife) can't have gluten, which means food is more expensive (although takeout is less of an option so that kind of takes the edge off).
Still, it's better than dieing sad and lonely!