All around the world, Sivacek (Sivacek 
) is an extremely rare unknown gender first name. Much more prevalently, Sivacek is the last name as well as the forename.
Mr, Arthur, Cheryl, Connor, Claire, Rhonda, Darcie, Taylor, Edward, Marilyn, Matthew, Melissa, Melinda, Michael, Suzanna, Beverly, Justina, Timothy, Emilija, Miroslav, Sheila, Sherri, Frank, Tracy, Tim, Mary, Miro, Mike, Paul, Gary, Jane, John, Judy, Kristine, Emil, Slavo, Clara, Karen, Katya, Peter, Phala, Diane, James, Tomas, Marie, and Christine