Interesting chart but probably not in the sense the makers intended. Unless they went door-to-door measuring every penis in Europe, this has to be self-reported lengths meaning it's just a question of how much men dare to exaggerate in any given country. Considering how mixed the genes are in Europe, don't think genetics would explain huge differences. So we got the French, who have their reputation, putting a few more inches in like the Italians (just think how many inches Berlusconi would add to his self-report). Spain is kinda mystifying with the macho culture, but maybe they're just honest. Everyone knows Finland has self-esteem issues so they wouldn't exaggerate as much as their neighbors in the happier scandinavia. Looking at Ireland, it's no wonder, they've been oppressed by the brits and maybe that Catholic ethic won't let them lie about their length...
This could be a start of a whole new field of science. Geopenology?