In all the world, Schlau (Schlau 
) is an extremely rare unknown gender forename. Much more frequently, Schlau is the last name as well as the forename.
Mr, Karl, Koby, Kurt, Kira, Kyle, Paul, Pete, Rose, Rona, Rita, Dave, Dale, Gary, Gail, Greg, Lisa, Lori, Luza, Jane, Jake, Josh, Bill, John, Beth, Anna, Ms, Max, Mel, Ben, Bob, Kim, Pat, Don, Lea, Jan, Jay, Tom, Mary, Mark, Matt, Moti, Sara, Sook, Alex, Andi, Andy, Aron, and June