Earlier this year, an independent commission led by a former US surgeon general said there "is not a compelling medical reason for US armed forces to prohibit transgender Americans from serving. Yesterday, on ABC's This Week, Defense Secretary Hagel said he's "open" to reassessing the transgender ban. Nathaniel Frank is visiting scholar at the Center for Gender and Sexuality Law at Columbia Law School author of Unfriendly Fire: How the Gay Ban Undermines the Military and Weakens America.