VIDEO : Catch Katie Couric?s ?Gender Revolution? For Free On Valentine's Day

Produced by Katie Couric Media with National Geographic Studios and World of Wonder Productions, the cable channel will also air a special encore of the documentary tonight at 9/8c. To better understand the complex social issue, Couric crisscrossed the U.S. to talk with scientists, psychologists, activists, authors and families to learn more about the role of genetics, brain chemistry and modern culture on gender fluidity. ?I?ve always hoped this documentary would be a spark to ignite conversations in every corner of the country around the evolving landscape of gender,? host and executive producer Couric told us.