It's pretty much explored every aspect of the trials and tribulations of high school from peer pressure to drugs to teenage pregnancy and sexuality.
It even faced the wrath of thousands of parents after a recent episode featuring Britney Spears was deemed unsuitable for its young audience.
But clearly not a show to cave under pressure, Glee has pushed its controversial boundaries even further with some girl-on-girl action.
Last night's episode of the smash-hit TV show finally showed what it hinted at throughout the first series of the show, as cheerleaders Brittany and Santana were finally seen getting it on.
Just a couple of scenes into the fourth episode of the second series, Brittany, played by Heather Morris, and Santana, played by Naya Rivera, are seen getting intimate on Brittany's bed.
As Santana kisses her neck, Brittany sighs: 'Oh, sweet lady kisses', before Santana smiles and says: 'It's a nice break from all that scissoring', referring to a lesbian sexual position.
The episode, which won't air in the UK until early next year, is called Duets and sees members of the William McKinley High School show choir pair up to perform a duet.
Something which brings Brittany and Santana's make-out session to an abrupt end after Brittany suggests they sing Melissa Etheridge's Come To My Window, in reference to the lesbian singer's song about song about her sexual orientation and activism.
But this prompts Santana to get up and leave as she tells Brittany: 'I'm not making out with you because I'm in love with you and want to sing about making lady babies' and says she's only getting off with her because her male lover is in prison.
A lesbian relationship between Brittany and Santana - who are known as Brittana - was hinted at throughout the first series after it was revealed in the Sectionals episode that they had had sex.
Brittany is also seen on the phone in another episode saying: 'If sex were dating, me and Santana would be dating'
The two characters were also at the centre of the controversy surrounding the Britney Spears episode after they recreated the Me Against The Music video, the song Britney recorded with Madonna, which the Parents Television Council slammed for having 'plenty of girl-girl bumping and grinding'.