See the about section of the Master Profile for Johan WIllhelm:
"They had one child:
4 i. Herman (1585-1642)"
Duke Johann Wilhelm of Jülich-Cleves-Berg
This is in conflict with Wikipedia: https://en.wikipedia.org/wiki/John_William,_Duke_of_J%C3%BClich-Cle... Duke Johann William's childless death in 1609, his inheritance was claimed by the heirs of his two eldest sisters: