Police facts show the teen, now 14, took photographs and filmed the acts involving the boy at a south side home during two days in December 2012.

An adult discovered 13 images and five videos on a mobile phone in May last year and reported them to police.

The teen pleaded guilty to charges of child pornography and having sex with a child under 10.

Magistrate Karen Fryar delayed sentencing the boy in the ACT Children's Court on Friday so he had more time to undertake counselling.

The teenager's counsellor told the court he had a history of "complex trauma" after being physically and sexually abused by family members as a child.

"When a child of that age is sexually assaulted, that child is going to come out with some very different ideas of how you relate to people," she said.

There was a low risk of him reoffending in the next six months if he continued in his present environment, the counsellor said.

The court heard the teen was now in a supportive foster home and school community and went to church each week.

A defence lawyer for the teen admitted there was a strong prosecution case and it was "a difficult sentence".

Prosecutor Anthony Williamson said while the crime was extremely serious, the teenager's age and history of abuse "reduces significantly his moral culpability for offending".

The boy was bailed under the condition he would continue regular counselling sessions.

Magistrate Fryar said: "It seems if I adjourn this sentencing to later in the year it will give myself and the community greater confidence that the likelihood of reoffending is being properly addressed."