This attractive woman in her late twenties goes to the doctors for a check up.
The Doc gives her a very thorough going over, puts his instruments away and then announces "Well, it's looks as though someone will be changing some nappies in a few months time"
Well, the chick is beside herself with joy as she says" Oh my god, I'm going to have a baby. I'm pregnant"
The Doctor shakes his head and says "No, you've got bowel cancer, but it was a good guess anyway".