The speculation had reached a feverished pitch, and the money was on Smithers.  But, it wasn't him.  The Simpsons' character about to come out is Marge's sister Patty.

Patty and twin sister Selma were long ago dubbed by Homer the “gruesome twosome”. 

After being snubbed by every man in Springfield, Patty decides it may be her and not the men. So, she of the purple hair heads out to find love.

She ends up in a bar, and is seduced a butch dyke. Ah, happiness.  Patty has found her true calling.

Patty comes out to Marge and Homer is horrified, as only Homer can be.

But, Patty and her new partner try to settle down to a blissful relationship, but realize they can't marry. No rights, no marriage no nothing.

Marge throws herself into the campaign to change the law so her sister can marry - and pulls it off!

Homer comes around, becomes an ordained minister thanks to an internet instant course, and performs the ceremony.

For months, since word that one of the Simpson's characters would come out, speculation has been rampant that it would be Smithers, the effete yes man to Mr Burns.

The Simpsons has been around for 14 years now and has never shied from taking on issues, but now it's up to the network.  Will it air before the November election?  Right now Fox has the episode scheduled for early in the new year.