Ratner, 42, best known for directing the Rush Hour films and X-Men- The Last Stand, caused controversy last week during a question-and-answer session at a screening of his new comedy Tower Heist, which stars Murphy.
He was asked about rehearsals for actors and replied: “Rehearsing is for fags.”
He later apologised but the damage had been done, with gay rights groups, as well as 6000 members of the Academy, crying foul.
“I am taking real action over the coming weeks and months in an effort to do everything I can both professionally and personally to help stamp out the kind of thoughtless bigotry I’ve so foolishly perpetrated,” Ratner said.
The film-maker also gave an interview on Monday on shock jock Howard Stern’s radio show in which he spoke about his past sexual conquests, masturbation, his skill at performing oral sex, pubic hair and the size of his testicles, the erotic habits of Hollywood moguls, his dislike of using condoms and his supposed habit of sending potential partners to his doctor to be checked for sexually transmitted diseases before he sleeps with them.
The director said that being asked to produce the Oscar show “was the proudest moment of my career,” but he didn’t want to distract from the academy “and the high ideals it represents”.
Murphy, too, said he was disappointed with not being able to continue in the hosting role.
“I was truly looking forward to being a part of the show that our production team and writers were just starting to develop, but I’m sure that the new production team and host will do an equally great job,” Murphy said.
Academy president Tom Sherak said: “I appreciate how Eddie feels about losing his creative partner, Brett Ratner, and we all wish him well.”