The younger of two brothers accused of raping their sister has told a court that his mother was "paranoid" about contact between her children.
The 13-year-old was giving evidence at Birmingham Crown Court where he and his brother, 15, deny charges of rape and sexual assault.
His mother alerted authorities after his younger sister, then aged six, claimed to have been abused.
The teenager said he had never touched his sister in a sexual way.
He told jurors his relationship with his mother deteriorated when he was in Year Seven at school.
"I kept getting in trouble at school and at home," he said.
Jurors were earlier told his mother had spoken to him about inappropriate touching, and alerted authorities after the six-year-old said she had been abused.
While giving evidence he was asked by his barrister, Jerry Hayes, why he thought his mother had said those things about him.
He said he thought his mother was "probably paranoid".
"If I was playing with one of my sisters in a room, she would come in and tell me 'you shouldn't, just the two of you, be in the same room'," he said.
The 15-year-old brother denies two charges of rape and four of sexual assault with a child.
The 13-year-old denies to counts of rape and two of sexual assault.
The trial continues.