I'm asking to settle a dispute between my mom and grandmother. My grandmother says she took my mother and a group of her friends to a 1972 concert in Dallas to celebrate my mom's 13th birthday. My mother says it might have been 1973, because that was the year "Let's Get It On" was released. That would've made my mother 14, not 13. Neither one of them have the best memories, so does anyone know if Marvin had a tour the year *before* "Let's Get It On"?