I see no reason why Gooch can't be a mousy, repressed, thirty-something woman who is working as a nanny and has been hired to take charge of Patrick, and who then "comes out of her shell" under Mame's tutelage. And for anyone who knew MAME before they knew AUNTIE MAME, as I did, it seems very strange to find that the one character was ever two.
And though Gooch's pregnancy may not be a funny subject, I do have to give it to Herman for finding a voice to Gooch's own wit in the song. Particularly the way she takes Mame's sayings and turns them around, in clever ways. I like to think that it's Gooch's reactions to her situation that are ironically comic, instead of the attention being on the pregnancy itself.