Quoted By:
I always figured Dawn was the most traditional Asian looking heroine, hence her popularity in Japan. She has long straight dark hair, she has smaller breasts and a thing frame like most Asian girls, and her short skirt gives her a Japanese schoolgirl look.
May on the other hand was a brunette with tomboyish style clothing and huge breasts, given her a more western look. May looked like a white girl traveling throughout Japan. Serena of course is French with the blonde hair and blue eyes, and being a Kalos native.
Dawn is the most Asian looking of all the girls. May and Serena feels white and Serena European, hence their larger breasts.