The episode, titled "Mr. Ratburn and the Special Someone," aired nationally on May 13. In it, Arthur attends the wedding of his teacher and his partner.
The state network instead showed a re-run of another Arthur episode, and its director of programming said Alabama Public Television (APT) has no plans to air the episode at another time.
Director Mike Mckenzie defended the move to AL.com in a statement, saying, "Parents have trusted Alabama Public Television for more than 50 years to provide children’s programs that entertain, educate and inspire."
“More importantly — although we strongly encourage parents to watch television with their children and talk about what they have learned afterwards — parents trust that their children can watch APT without their supervision," Mckenzie said. "We also know that children who are younger than the ‘target’ audience for Arthur also watch the program.”
He confirmed that APT previously pulled another episode of "Arthur" in 2005 that showed Buster, the namesake character's bunny friend, having two mothers.
A petition on Change.org urging Alabama to air the episode received more than 3,000 signatures of a 5,000 signature goal as of Tuesday morning.
Fox News' Ann W. Schmidt and the Associated Press contributed to this report.