A 48-year-old German suspected of fathering at least seven children with his stepdaughter is standing trial on allegations that he abused her and two other children for more than 20 years.
He is also accused of forcing two of them into prostitution.
The man, identified only as Detlef S. in line with German privacy rules, went on trial today on charges of sexually abusing minors in his care between 1987 and 2010, and with facilitating sexual acts with minors.
He faces up to 15 years in prison.
The three alleged victims - the man's daughter, stepdaughter and stepson - have joined the trial as co-plaintiffs, as allowed under German law.
German media have reported that Detlef S. was a truck driver who lived with his family in the small town of Fluterschen, near Bonn.