Well, I can help you with that answer. I am asian, but I know what I got, and not what other asian brothers got, but I researched this because I wanted to see if it really wasn't a stereotype. I was getting tired of the asian jokes -_- and was determined to see if there was some truth to it. This is what I discovered.
Apparently there is a suspendatory ligament between the penis and the pelvis in which the penis retracts in and out from. I guess a visual of this is something like a tube within a tube. For blacks, whites, and asians, these are all differently angled and retracted differently. For black guys, the penis hangs pretty much as far from the suspendatory ligament, thus most of their penis lies outside the body. Their erection elevates a little as well from the angle of the ligament. White guys have less suspension, thus on average a shorter penis, but is angled in such a way that their penis is pretty much perpendicular to their body. As for asians, who get the "short end of the stick" (excuse the pun =) ), much of their penis lies inside the ligament, but angles up really high.
There is some theory that exercising this ligament and stretching it will yield in a bigger penis, but this could just be proproganda to make money for their "guaranteed program".
Anywhoo, I'm new to the forum, this is my first post, I joined because I am interested in all aspects of health and enjoy learning anything about it. If anybody has any questions concerning exercise (not your penis, though I know a bit on the kegels), weight loss, weight training, etc, feel free to ask me, I recently got my personal training certification! Hope I brought in some plausible information.