From the Matt Baume Web site:
On This Day, October 9, in 1977, in a landmark episode of the CBS series, All in the Family, America is introduced to a family member who was in a long-term relationship with her gay partner.
It was the night CBS aired the episode, "Cousin Liz." According to Matt Baume, in just a half hour the show did three amazing things: it showed America that they could have queer family members. It depicted what may be TV's first gay marriage, and may have changed the course of an election. Watch Matt's excellent video covering the episode above, which he published in 2015.
Check out this and other videos; Matt Baume's podcast, The Sewers of Paris; his book, Defining Marriage; and more at his Web site here.