Alabama Public Television (APT) has refused to broadcast a cartoon which shows a same-sex wedding.
The first episode of the 22nd series of children's programme Arthur features the character Mr Ratburn marrying his aardvark partner, Patrick.
But APT instead ran an old episode, and announced it had no plans to show the premiere.
Programming director Mike McKenzie said broadcasting it would break parents' trust in the network.
In a statement, Mr McKenzie said "parents trust that their children can watch APT without their supervision", and that children "younger than the 'target' audience" might watch without parental knowledge.
Show creator WGBH and broadcaster PBS reportedly alerted local stations in April about the episode, and Mr McKenzie said this was when they decided not to air the show.
Arthur is a joint Canadian/American series which debuted in 1996 about an eight-year-old anthropomorphic aardvark named Arthur Read and his friends, who live in the fictional Elwood City.
APT previously refused to broadcast a 2005 episode of the series which depicted Buster, a rabbit, visiting a girl who had two mothers.
Substitute teacher Misty Souder told news website AL.com that she and her daughter were disappointed the episode did not run and had contacted the network about it.
"I never thought I'd be going to battle for a gay rat wedding, but here we are," she said.
A 2018 Gallup poll showed 46% of people in Alabama identified as conservative, second only to Mississippi among all 50 states.
Earlier in May, Alabama passed a law banning abortions even in cases of rape and incest, the latest US state to restrict access to abortions.