The map doesn't look all that accurate to me, but perhaps the little Italian bambinos are good in bed but not prolific in bedding down with every lothario that walks by. Did I actually say "lothario"?! I didn't even know I knew that word...
They seem to be very family-oriented. The Italian girls I've ever known (including the one I'm seeing right now) seem to need a commitment from a man before giving it up. I may be entirely wrong and speaking only from my own experience... not sure.