I'm one of those in which the genetic crapshoot came up "should totally be a redhead, but let's make her dark blonde". I have the complexion and coloring and heritage to be a redhead, and then ended up with a blonde hair color that washes me out and makes me look ill. The only real red hair on me is the carpet.
So, I dye.
People are shocked when they find out I have to dye my hair because I look that much like a natural redhead. "But you're Celtic! You've got freckles! And a temper! And you snark! Why??"
I don't know if coloring or heritage have anything to do with libido/drive. My mother remarked that I definitely have a higher libido than she ever did (she's brunette). All I know is that I spent my teens in complete frustration because I was a redhead by then and I was quite willing, but I was not attractive enough for guys my age, and older men were allergic to jailbait.