Interview by Charles Weiner at the website of the American Institute of Physics:
Weiner: Let me ask at this point whether there were any brothers or sisters in the family?
Feynman: There was a sister. There was a brother that came after approximately three years. Or maybe I was five, four, six, three, I don’t remember. But that brother died, after a relatively short time, like a month or so. I can still remember that, so I can’t have been too young, because I can remember especially that the brother had a finger bleeding all the time. That’s what happened — it was some kind of disease that didn’t heal. And also, asking the nurse how they knew whether it was a boy or a girl, and being taught: it’s by the shape of the ear — and thinking that that’s rather strange. There’s so much difference in the world between men and women that they should bother to make any difference, a boy from a girl, with just the shape of the ear! It didn’t sound like a sensible thing. Now, I remember that I had another, a sister, when I was nine years old, so it’s possible that I’m remembering my question at the age of nine or ten, and not at the age of the other child, because it sounds incredible to me now that I would have had such a deep thought about society at the earlier age. I don’t know. I can’t tell you what age I was, but I remember that, because it was an interesting answer. I couldn’t understand it really. They make such a fuss — everybody dresses differently; they go to so much trouble, their hair different — just because the ear shape is different? What sort of an answer is that?
More here.