There is no such thing as 'the fawn gene' any more than there is 'the blue gene'. Fawn is dilute cinnamon, not a recessive of cinnamon. Cinnamon is recessive to chocolate which is recessive to black. I think it's a stunning colour on self cats. I don't like it on tabbys as there isn't much contrast, and it gets very pale & wishy washy on colourpoints. This is Basil, a fawn Oriental.