I have on occasion wondered about the evolution of a mole. Babies usually don't have any (birth marks, yes--but not actual moles). And pretty much every adult has at least a few. When do we get them? Surely they just don't appear over night.
I think I have an answer now, as far as when they first show up--age 3 1/2. As I was putting Evan's pajamas on, I noticed the tiniest mole under his left armpit. I asked Jeremy if he'd seen it, and he had not seen that one but had recently noticed one on the side of Evan's neck. Another first for the baby book :)