In the entire world, Sandersen (Sandersen 
) is an extremely rare masculine forename. Much more frequently, Sandersen is the last name as well as the forename.
Mr, Knut, Paul, Ruby, Rune, Dane, Geir, Greg, Lisa, Liam, Lori, John, Joel, Jill, Thor, Tina, Tine, Eric, Erik, Erin, Hans, Unni, Kyle, Marie, Kurt, Aren, Ms, Sã, Kim, Pia, Jan, Jim, Tom, Eli, Ida, Ole, Mari, Mark, Matt, Mads, Sara, Siri, Sune, Sven, Alan, Anna, Anne, Carl, and Marit