Via Professor Mankiw’s blog, I don’t quite know whether this is a genuine academic paper or a submission for the Ignobel Prize. As Professor Mankiw says:
These may be the least expected sentences I have read lately: “This paper explores the link between economic development and penile length…. The GDP maximizing size is around 13.5 centimetres.”
Update: Someone mentioned in the comments that the Ignobel Prize papers are chosen from among actual scientific papers – that’s what I was thinking. I wondered whether this was a bid for an Ignobel by having an actual paper in the Helsinki economics series, but for the purpose of the Ig. That’s my current theory, anyway. Of course, it also calls to mind the famous lemons-highway fatalities graph, in the department of “correlation = causation, not.”