This is an age old question and I saw a program on tv about it. What they said was that a man's penis size is generally inherited and has nothing to do with nationality. Penises appear smaller on Asians because their bodies are smaller so they have to be proportionate. Penises appear larger on Afro Americans because their bodies are bigger. So if you are a large Asian then your penis should be larger to match the rest of your body. This is why people say big feet and hands = big penis. It's all a matter of proportion and never a clear indicator however because many people are misproportioned anyway.