A WARWICK man told police he secretly recorded videos of his sexual encounters with his stepdaughter as an "insurance policy" in case his behaviour was ever questioned.
The man, who cannot be named to protect the identity of his alleged victim, told police in an interview that the sexual relationship was consensual and the videos depicted that.
But Crown prosecutor Noel Needham told Brisbane District Court that the man used controlling behaviour and threatened to leave the teen's mother to coerce her to engage sexually with him.
He said the man once showed her some of the DVDs he made and allegedly threatened to show people what she was "really like", calling her a slut.
Mr Needham said the teen, who also fell pregnant, believed her life would be ruined if the videos got out.
The girl was allegedly aged between 13 and 19 when the offending occurred.
The man, 56, is facing a judge-only trial before Judge Brian Devereaux after pleading not guilty to more than 100 charges, mostly rape.
He has also denied maintaining a relationship with a child, making child pornography, making recordings and observations in breach of privacy and multiple sexual assaults.
Mr Needham said most of the offending began after the girl's mother and stepfather began sleeping in separate bedrooms.
He said the man realised the girl was pregnant when she missed her menstrual cycle and arranged an abortion for her at Caboolture.
Mr Needham said they stayed with family at Nambour and then the sexual encounters became more frequent after the teen had a contraceptive implant placed in her arm.
"After that point the defendant would come into her room or she would go into his room frequently," he said.
"She knew sexual activity in one variety or another was going to occur when he demanded it of her."
Mr Needham said hearing footsteps in the hallway kept her awake at night but she could exercise some control and get a good night's rest in her own room if she went to him.
"Secondly, she'll tell you she would watch the television and allow her mind to go elsewhere as her body was exploited," he said.
"This is not consent."
The court was told there were many videos and photos on DVDs and SD cards as well as photo albums of the activities.
Mr Needham said the man used his role as the teen's primary care giver to modify her behaviour to attend to his sexual needs and sexually exploit her.
He described the power imbalance as "the metaphoric gun to the head".
The trial is set down for two weeks.