You know, there are some people who have theorised that traditionally (I am talking back when we were cavemen and cavewomen) our babies NEVER crawled, because instictively we knew it was unsafe to place a baby who couldn't walk directly on the ground (ie: too much danger from dirt, rocks, predators, etc). In fact, anthropologists have suggested that it wasn't until we lived in huts with "floors" that we ever stopped carrying our babies. Google it and see for yourself.

Needless to say, personally I think the whole "stages" of development thing is a crock. I realy doubt that cavebabies all followed the same patterns while their mums gathered berries and their dads hunted wooly mammoths.........