 Jos Stam's maternal grandfather was the Dutch politician Sim Visser.His father Jos Stam was born in Rotterdam (Netherlands), and in 1944 at the , he was deported by the Nazis to Germany, where he had to repair railroads behind the western front, until being liberated by the American troops in 1945.He emigrated to the US in 1956, where he worked as a researcher for the DuPont de Nemours Company.