Authorities allege the girls' parents "gifted" their oldest daughter to Lee Donald Kaplan because he helped them financially.
Jurors in Bucks County convicted the 52-year-old on all 17 counts of rape of a child, statutory sexual assault and other offenses. The conviction came a year after a neighbor's tip prompted authorities to search his Feasterville home. Kaplan fathered two children with one of the girls, the first when she was 14.
His defense said Kaplan was married to the girl in the family's eyes and that he didn't abuse the younger children. A sentencing date hasn't been set. The parents of the six girls are awaiting sentencing on child endangerment convictions.