Steve Landsburg's new book is out! The title of the new book is, yes, you get it right: "More Sex is Safer Sex."
Here is an advance praise from another Steve of Freakonomics fame:
"Steve Landsburg proves once again that he is better than anyone else at making economics interesting to noneconomists. Landsburg is provocative and playful in his mission to demonstrate how an understanding of economics will change the way you live your daily life. I loved this book."
Here is more info about the book.