I've had a few messages recently telling me that Charles Darwin had red hair. I'd love this to be true, but I've had a search round on-line and can't find a reference for it. The one webpage describing his appearance states it was 'dark brown'. Maybe there's a contemporary description of his appearance out there somewhere that does say red, but for the time being I'll have to leave him at the door of the club.
On a related note I did find a Telegraph article stating Darwin was interested in the relationship between behaviour and hair colour. The article refers to letters found where he discusses the idea that blond women were less likely to marry than brunettes. The correspondence was with a Dr John Beddoe, who I'm guessing is the same Beddoe that provided me with so much information for this page;-