Please explain the etymology of straight?

The use of the word "straight" for a male or female hetrosexual, is derived from the antonym "bent" as in homosexuals are bent, they were referred to as bent, or benders, as in wrong doers, anything ilicit in the 1940`s was referred to as bent.."I got this Morris Oxford off a guy in Dartford, `course its bent, but I got it for half a pony"..That Geezer down the pub, Eees as bent as a nine bob note" Being homosexual was ilegal in the UK until the mid 60`s, when a bill in Parliament was passed, to make it legal..as the old joke goes.Harold Wilson says to Ted Heath..."What do you think we should do with this homosexual bill"..Ted Heath says.."Pay it " !