In Japan it seems that nipple color has such a powerful significance than many woman are seeking cosmetic assistance in changing them from brown to pink.
And there’s a belief in Japan that pink nipples denote purity, while brown ones … don’t. A female plastic surgeon I know who works in Tokyo put it this way: “Japanese girls want to have pink nipples because Japanese guys like them. For some Japanese men, the less sexual experience a woman has, the better. Little experience means she is clean and precious for them.”
It turns out some women in Japan really feel this way. Why? “Because pink is cute,” she told me.
VIA The faster Times article by Daniel Krieger: Why the Japanese are Turning Their Nipples Pink
And one last bit from a healthcare perspective: What the Color of Your Areola Tells About You (Yahoo).