SEX could also mean XES (Greek Chi, Xi and Sigma) which is equal to 666 but the sexual content is quite obvious. The word sex itself has the same origin as the word six. In German six is sechs and sounds a lot like sex. Among other things sex defines our gender. The number six is related to humans and 666 is also.
Revelations: "for it is a human number"...
BTW, nice site!