2013-03-21
Explanation
This comic imagines an app called "Conception Connection" that calculates the approximate date of your conception from your birthday, then cross-references it with historical events to determine what world event most likely inspired your parents to have unprotected sex. One character demonstrates with his own result: "Most likely historical event that aroused your parents: First flight of the F-117 Nighthawk" (the famous stealth fighter, which first flew in 1981). His friend looks at her own result and just says "Huh," suggesting something awkward.
The comic then cuts to the "Later..." panel where a young man, now shirtless and strapped to some kind of apparatus with a military gas mask, calls his parents (one of whom is a military officer) and asks: "Mom, Dad... do you have a fetish for the declaration of martial law in Poland?" His father, in full military dress, nervously responds "Why do you ask?" The declaration of martial law in Poland happened in December 1981, which would line up with a September 1982 birthday. The joke is the horrifying realization that your parents''' sexual proclivities can be reverse-engineered from publicly available data.
The humor comes from the mortifying intersection of personal and historical -- the idea that major world events, including military and political milestones, might have served as aphrodisiacs for someone'''s parents. The votey panel simply reads "50 internet points to whoever makes it!" -- Weinersmith challenging his audience to actually build the app.