In this post I'll concentrate on the photographs of his children, Jean and Geneviève. Take a look at this one:
This picture is taken by Martial Caillebotte around 1898, and you see a photograph of his son and his daughter. Yes, there are not two girls in the picture, but a big brother and his little sister. I found this sort of interesting, and also, somewhat disturbing.
Then there is this photo, taken at the grandparents' house, with the same two children, Jean and Geneviève Caillebotte:
Then, there is this series of photos, depicting Jean's haircut. (Propably his first.)
I was trying to understand the whole thing. Why have Jean look like a girl, and then make a whole big deal of cutting his hair and dressing him as a boy? I was wondering if this was his father's sick artistic consept, and that the boy just had to go through with it, endure those years until the hair was long enough for the photoshoot?
Then, a friend of mine had another idea: Maybe it was him, the boy, wanting to look like a girl, and his parents being open-minded about it, until one day, he had to let go of the girl look? After all, he doesn't look too happy...
Well, now I actually have another explanation: In those times, in certain circles, boys were dressed like girls until the age of ten, when the hair was cut, and their masculinity began. Interesting. Very interesting, and I've never before heard of this custom, at least not in France.