A volunteer ethics teacher has been stood down from a Sydney primary school for telling students that Aboriginal and Torres Strait Islander Stolen Generations were taken from their families because of poor parenting.

The incident has raised questions about whether volunteers should be allowed to teach ethics and religion in public schools.

The Special Education in Ethics (SEE) discussion, involving year six students at Dulwich Hill Public School, began as one about homelessness but became heated when one student mentioned the long-term trauma of the Stolen Generations.