Ernie and Bert are not gay. They're puppets. They don't even have legs.
In one of the great low points in western civilisation, the Children's Television Workshop actually found themselves having to issue a press release saying this in the early 90s in response to a rising protest that Sesame Street was promoting an immoral gay lifestyle. Not that the CTW was trying to condemn homosexuality, or anything, it was just that it was an issue that they didn't particularly want to take a stand on, and that they were baffled that anyone could garner moral outrage from a closed-minded condemnation of a wholly imagined subtext in a misinterpretation of a children's TV show.