Found these online. There has been a lot of talk in recent years about the drop in the age of puberty. Kids are growing up (in the absolute physical sense,) earlier.

Maybe it is better diet, maybe exposure to light, nobody is really sure. It has dropped several years in the past 100.

Looking at these old photos, I am struck by how young the kids look. Probably this group is pre-selected for poor diet, they do not appear to be children of the affluent. But if the ages are correct, they would look a lot more grown up today. What do you guys think? I am thinking that my age of sail, age of Marlowe kids may have looked kid-like longer than I am calibrated for.

There is one very strange study out there that says that a girl who lives in the same house with her biological father will have later onset menarche than a girl who does not. That is one of those weird findings you just want to poke at until the facts make sense, so strange.

http://www.cbsnews.com/pictures/childrens-mugshots-from-the-1870s/