Iowa City native Zach Wahls skyrocketed to celebrity after a video of his speech before the Iowa Legislature became the top political youtube video of 2011. Now he’s written a book called My Two Moms: Lessons of Love, Strength, and What Makes a Family that looks at growing up with two lesbian mothers. Ben talks with Zach about the book and his newfound celebrity, which includes an appearance this week on Late Night with David Letterman.