People generally make fun of the Chinese and the Japanese for their looks and the distinctive features.Even higher, the ultimate problem in differentiating a boy and a girl.I though initially that it was just an exaggeration and it was wrong.I felt, may be it was difficult for us, the non-Chinese and non-Japanese people to differentiate them.But, when i saw “Shichinin no samurai”,the IMDB top Japanese movie, where one of the samurais who himself was a Japanese couldn’t distinguish between boy and a girl when Mando’s daughter had disguised as a boy to be away from the eyes of the samurais.Now,i accept that there is that difficulty in identifying.May be, you just have the option of talking to them and knowing if they are sir or madam.