Career
Osselmann was born in Duisburg. His father, Friedrich Osselmann, played water polo for West Germany at the 1956 and 1960 Olympics, whereas his mother, Birgit Klomp, competed in swimming at the 1956 Games.
Osselmann was born in Duisburg. His father, Friedrich Osselmann, played water polo for West Germany at the 1956 and 1960 Olympics, whereas his mother, Birgit Klomp, competed in swimming at the 1956 Games.
