More fun from the WSJ: an article on the cost of having a third child.
It seems that if you have a third child you need a house with more than three bedrooms, which is hard to find. You don't fit at restuarant tables, not even at Burger King. You can't fit all the car seats in your convertible, so you have to buy a minivan. You can't put five people in a room at fancy hotels.
Having grown up in circles where a family with three kids was considered small (and being the fourth child myself), I was highly amused by these challenges. But now my mom's statement that three children was the worst number to have makes sense. At three you outgrow all the things meant for families with two children. After that, it doesn't really matter how many more you have.
Either that, or life just got better when I came into the world.