One nit-picking, yet somewhat major, correction to what you said, Poly:
This really should say:
“The account of both Joseph and Mary says they are skeptical of what’s supposed to happen; they know very well where babies come from, and the account says they hadn’t done it”
Nit accepted, but it was pre-picked: I had assumed that people would read the material after the dash (–) as being a description of the “circumstantial account” to which I had just made reference, and it’d be assumed that I was recounting what the account said.
Good point, though, in case others failed to read it that way.