"So I was looking at the unmarried partners visa info today and it said we need to live together for 2 years first but we'll be married by then."
"Did you know you can get an unmarried partners visa even if we were the same sex?"
"Oh yeah? Cool."
"Yeah! So which would you rather have us be, both girls or both boys?"
"Hmm... I think I'd rather you stay a girl so I'll be a girl too."
"OMG I totally agree. I'd rather you be a girl than me be a boy too!"
"I'm glad we had this conversation before we got married."
"Yes, I'm glad to know that if one of us has to have a sex change, we agree it's you."