Is there such a thing as blonde pubic hair that is really yellow of almost white?

Eyebrows are the real clue. Golden yellow on top without any dark brown in it and you should see the same below. So yellow yes but white? Doubt that ever...Blonde's will almost always have a darker shade below - On a nude beach its not uncommon to see brunettes with shades lighter then blonde's and redheads - Can be dark red on top and light red below yet the eyebrows will almost always match her pubic hair.