The Disney Channel introduced its first gay characters on Sunday during an episode of Good Luck Charlie.

In the episode – the fourth in the sitcom's final season – preschooler Charlie (played by Mia Talerico) has a new friend with two moms. The family comes over to the Duncans' home during a playdate arranged by Amy and Bob Duncan (Leigh-Allyn Baker and Eric Allan Kramer). (A clip from the show is embedded on this page. Visit our video library for more videos.)

While the characters are only expected to appear in this one episode and the storyline is secondary to the plot, the Disney Channel recognized the groundbreaking nature of including gay characters in its original programming.

“This particular storyline was developed under the consultancy of child development experts and community advisers,” a spokesperson told TV Guide in June. “Like all Disney Channel programming, it was developed to be relevant to kids and families around the world and to reflect themes of diversity and inclusiveness.”

Social conservatives in 2012 criticized a Disney Channel ad campaign for including a teen with two moms.

(Related: Disney knocked for featuring teen with two moms in “Make Your Mark” campaign.)