BBC theory has been around "
since at least the 15th century".
Anthropologist John Baker is
convinced by the evidence that West Africans are more sexually potent and better endowed, especially when flaccid. The evolutionary psychologist Phil Rushton believed that blacks were better endowed than whites. From the most convincing studies I've seen, blacks appear to be only slightly larger than whites (within half an inch) but small differences on average can make for considerable differences on the extremes (male vs female IQ is a good example). It's probably true then that there is a considerably higher ratio of blacks with BBC's (8+ inches) than whites with BWC's. People also perceive blacks to be bigger and taller even if they are the same size; their dark colouration gives them more of a fear factor. It's possible then that black cocks look bigger, other things being equal. Whether black sexual prowess is entirely real or imagined, it still gives blacks an advantage in bedding women. It's also possible that the taboo thrill of copulating with a white woman increases arousal more for blacks, resulting in larger, firmer erections.
BBC theory is part myth, part reality. Porn exaggerates it because it's playing to the stereotypes and fears of its largely white, male audience, and more cynically, trying to cement black masculinity as the cultural ideal as part of a Jewish plot. It could also be argued that white scientists had an incentive to exaggerate black penis size in order to help portray blacks as savage jungle animals, totally controlled by their base urges, and to make it imperative that white men protect their women from the "bestial black monster".
