There's a subsequent twist in The Crying Game where they go back to the bar they've been to before, and Fergus sees the women there quite differently than before, as does the audience.

I didn't get that brain teaser at first when I was a kid, but I was furious at myself when I turned the page upside down (it was in a book or magazine or something, with the answer on the bottom), as my own mother was a doctor.