the english word origin dates back to the plantation. properly pronounced it's muthafucka not motherfucker, and it is a generic word for white folks since the 1600s. but don't take my word for it:
http://www.urbandictionary.com/defin...m=motherfucker
Motherfucker (also contracted forms mother and mofo and, phonetically, in African-American vernacular speech, muthafucka) is a common insult and profanity in the English language and is widely considered obscene and inappropriate. By virtue of its history of usage, motherfucker generally is regarded as African-American in origin. Literally, it accuses one of violating, perhaps, the oldest taboo known to humankind, incest. However, as with most epithets, its use is pejorative, rather than literal. Historically, it was a vicious taunt, a damning insult -- and a veiled allusion to the destruction of black male familial hegemony under chattel slavery. The power of the word was that it attacked one's sense of manhood. Regardless of its historical or cultural context, however, many consider motherfucker the mother of all curse words.