First, for the poster that said animals don't bf past infancy, that's not true. If you compare time spent nursing with lifespans and developmental abilities, animals nurse well into what some here call "childhood." Higher order animals, such as apes, chimps, etc. nurse to what would be the human equivalent of six or seven years. There is a biological need for it. Also, kittens are born with teeth, should they never nurse?
For the poster that wondered if bf'ed babies were healthier because their moms stay at home with them, that isn't true. Breastmilk has something like 114 chemical compounds that formula can't duplicate, and many of the nutrients in formula aren't able to be absorbed by a babies digestive system. Also many bf'ing moms do work and pump. I understand that your question wasn't an attack, I'm just answering it.
Goobergal- A truly lactose intolerant baby can't drink soy formula either, as there is lactose in it as well. You would have just needed to avoid dairy in your diet.
A side note that improper information given by medical professionals is one of the top reasons the AAP lists for breastfeeding failure. I urge anyone in the medical community not to give any sort of breastfeeding advice unless you really are up to date. I know more than most doctors I've encountered and that's really sad. The misinformation given by posters in this thread that claim to be professionals is a prime example of that.