2014-04-19
Explanation
The Joke
A young girl asks her teacher, "Mrs. Jeffers, what's sex?" The teacher, flustered, stammers and then decides to explain it in terms of biology: "At its most fundamental, sex is an exchange of information. Does that make sense?" The girl enthusiastically says "Yes!" with a DNA helix shown in the background. In the final panel, the girl tells her father, "Dad? I had sex with my biology teacher!"
The Humor
The comedy arises from the teacher's attempt to use a technically accurate but overly abstract biological definition of sex. In genetics, sexual reproduction is indeed an "exchange of information" -- organisms swap genetic material. The teacher thinks she has given a safe, sanitized answer. However, the child interprets "exchange of information" literally and broadly: since the teacher exchanged information (taught her biology), the girl concludes they "had sex." The father's horrified expression in the final panel shows the disastrous consequences of the teacher's vague euphemism.
The joke plays on the classic comedy of miscommunication between adults trying to explain sensitive topics to children and the children interpreting things in the most awkward way possible.