I'm surprised you would even have to ask this 
question. I find comments like those you 
overheard no less foolish than racial 
stereotypes. Growing up in an area with a large 
Asian-American population, I've heard all the 
jokes. Bad driving. Good at math. Sexual 
practices. It's all rubbish made up by insecure 
people. I myself am a BIG dude. I'm 6'3", 290lbs 
of pasty-white Irishness. However, when I go to 
cons here in the states, I see a myriad of body 
types, genders, ages, races, and tastes. I really 
don't see a dominant "type" at these things. Hope 
that answers your question.