Foreign women tend to be direct, independent and more mature than the typical chinese person.  These traits intimidate most chinese men, who prefer their women to be immature, demure and dependent on them.  Also western girls usually like manly men.  Asian men are smaller and more feminine, generally speaking.  Western women expect the man to take the lead, be affectionate, thoughtful, passionate, and outgoing (according to a recent study I read).  These are not common traits in Chinese men. Incidentally, I haven't heard anything that confirms that size matters to women. Accept for the few women who have dick fetishes, as long as its within average range, it can do the job for them. Women are much less obsessed with dicks than men.