Mrs McGlinchy (we're protecting the innocent here) becomes pregnant after years of trying. At the birth, the consultant says that, as a teacher, she would understand the importance of students being able to observe and learn.
She says she is content for a group of students to be present. As labour progresses, she has to go through the whole gamut of legs in stirrups, forceps delivery etc. At last, the baby is born, washed and placed in her arms.
The consultant thanks her for allowing the students to watch her Herculean efforts, at which point a young male student approaches her and says:
"Excuse me, Mrs McGlinchy, but didn't you used to be Miss Smith who taught me Higher maths?"