Gallup Vault: Teen Brides Acceptable to 22% in U.S. in 1937 November 10, 2017 How old should a girl have to be to legally marry with her parents’ consent? Gallup posed this question to Americans in one of its earliest polls, in 1937. CONT. Lydia Saad, Gallup Share:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on Reddit (Opens in new window)Click to email a link to a friend (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Tumblr (Opens in new window)Click to share on Pinterest (Opens in new window)MoreClick to print (Opens in new window)