I hope to God not. It'd be Jaws doing the pole-vault.
I'm horribly torn. Narratively it feels like a pregnant Zoe would be cheesetastic and shark-jumpy and painfully pandering to the audience's cheapest sentimental desires, and yet... I have those very same cheap sentimental desires myself. It's massively to the credit of Gina Torres and Alan Tudyk and Joss and every single writer and director on the show that one small part of my brain genuinely and insanely believes Zoe to be real.
As much as the thinking story-consumer me turns up her nose at the possibility of Pregnant!Zoe, the craxy part of me fiercely wants that for her, in his memory and honor, for her messy and complicated consolation, and because any child that came from the two of them would grow into an amazing person who'd improve the 'Verse just by existing, and we already don't have enough of those people now, so how much worse will it get in 500 years?
I completely understand that Zoe is fictional and her grief is fictional and the hypothetical child she and the also-fictional Wash talked about possibly trying for is just a fiction in a fiction, but I can't shake the feeling that their being fictional does not in the least prevent them from being Real, and I have this huge fierce sister/friend/admirer desire for her to have a child for its own sake and her sake, crap plots be damned.
I blame all the good acting and writing and directing, and also too many readings of The Velveteen Rabbit. Curse you, Margery Williams!