Worldwide, Kostiou (Kostiou , Костю ) is an extremely rare unknown gender forename. Much more prevalently, Kostiou is the last name as well as the forename.
Костью
John, Joni, Nick, Amber, Vicky, Andrea, Kostas, George, Jessica, and Anastasia
, Костю 
) is an extremely rare unknown gender forename. Much more prevalently, Kostiou is the last name as well as the forename.