What use is a baby ?

Often when people are haggling for funding for blue-skies research, someone will employ the classic cliche : what use is a baby ? It's a good line. Everyone knows that babies are useless but eventually some of them become really useful people, like Michael Buerk and Scarlett Johansson. And eventually, so science tells us, we'll be able to have designer babies. Which begs the question : are babies really as useless as the old proverb would have it ? Or, to put it another way, if babies were a product you could buy from JML then what would the sales pitch be ?

I guess we must first start by trying to fit them into some sort of category. Clearly they belong in the house so must be some kind of household utility. What is it that they actually do ?

1) Eat
2) Sleep
3) Poop
4) Pee
5) Make noise
6) Increase entropy
7) Move about
8) Hit things
9) Change channel
10)Turn lights on and off

All of which could easily be used in a marketing campaign. They are in fact extremely useful. Observe :

Sometimes I wonder if I have too much time on my hands, contrary to all available evidence. Oh well.