Oh yeah, Larry Gelbart would be humbled by great jokes like:
"What is so unusual about a Lesbian and a fighter pilot having a baby?"
"He is not a fighter pilot."
And then a cock joke. This is the TRAILER.
Now let's look at some of the reviews:
Telling a blended family tale that I feel like we’ve heard many times before, and in far better ways, One Big Happy delivers stereotypes galore where a script should be. With frat-boy-level pee jokes and unfunny quips about lesbians, straight guys and Brits all over the place, it creaks along like the worst aspects of Three’s Company – and that’s just in the first few minutes.
-- Deadline Hollywood
One Big Happy, an amateurish bungle of a comedy, has a single idea that's impossible to miss: the script hammers it home so strenuously, the writers must think we're as dimwitted as their creations.
-- USA TODAY
One Big Happy is a loud, frantic sitcom so eager to please, you may want to avert your eyes. That’s assuming you continue watching past an early punchline, which I will now quote in full: “Vagina, right on the chair!”
-- Yahoo TV
As a sitcom, it’s as retrograde as it gets—a Three’s Company retread where instead of getting starkly different personalities, the characters get different sexualities. (Or, in Prudence’s case, an accent.) Hijinks barely even ensue, replaced instead by broad lesbian clichés and stereotypes that are only recognized as jokes when the unsettling, maniacal laugh track kicks in.
-- The Daily Beast
It’s no longer unusual to find nontraditional families on television and for people in those families to be having babies. Apparently the makers of "One Big Happy" an intelligence-insulting sitcom that begins Tuesday night on NBC, haven’t noticed, because every minute of their show screams: “Hey! We’ve got a pregnant lesbian! Bet you’ve never seen that before!”
-- NY Times
Basically every punchline involving Cuthbert's character revolves around her being a lesbian and having lesbian footwear and clothes and interests.
I think the best you could say is that she meant the line as a joke. Y'know, she was trying to be Ellen but funny.