There are no vegan societies for a simple reason: a vegan diet is not adequate in the long run.
Protein deficiency is one danger of a vegan diet for babies. Nutritionists used to speak of proteins as “first class” (from meat, fish, eggs and milk) and “second class” (from plants), but today this is considered denigrating to vegetarians. . . . An adult who was well-nourished in utero and in infancy may choose to get by on a vegan diet, but babies are built from protein, calcium, cholesterol and fish oil. Children fed only plants will not get the precious things they need to live and grow.
UPDATE: I love this from the Amazon reviews, where a flamewar is underway:
The Vegans are on the attack... Planck just wrote an op-ed piece in the NY Times today (May 21) discussing the lethality of unsupplemented Vegan diets (after yet another couple was convicted of murder for starving their infant by withholding animal protein.) But now it's payback time, so the Vegans have come to try to destroy Planck for bringing science, not sentiment, to the subject of nutrition.
Politics and PETA won't keep a baby alive when it's deprived of the essential amino acids that can only be found in animal protein. And none of these Vegans have read Planck's book...I have, and it's good.
Yes, it is. I had a girlfriend who was on a vegan diet. She came down with Kwashiorkor. Luckily, the folks at Cornell Student Health diagnosed it quickly, even though it's a protein-deficiency disease normally found in starving third-world children, because they had seen it so often among women on vegan diets.