In all the world, Küpper (Küpper 
) is an extremely rare unknown gender first name. Much more prevalently, Küpper is the last name as well as the forename.
Max, Bert, Karl, Kurt, Kira, Paul, Ralf, Rolf, Rene, Rico, Rita, Ruth, Rudi, Dirk, Gerd, Lara, Lars, Leon, Lena, Lisa, Luca, Luis, Axel, Amon, Arne, Arno, Ben, Kai, Lea, Jan, Ton, Tim, Eva, Ina, Ulf, Udo, Lutz, Ute, Marc, Mira, Mike, Sven, Alex, Anna, Anne, Anni, Anja, Anke, Uwe, and Jana