1982– United States 235 cm 7 ft 8 in Broc Brown Former tallest teenager in the United States.[32] 1998- United States 235 cm 7 ft 8 in Cecil Boling Was 7'8 but shrank to 7'0 since his legs were replaced with artificial legs 8.5 shorter.[33] 1920–2000 (79) United States 235 cm 7 ft 8 in Brenden Adams Former tallest teenager in the world.