"She was very angry and couldn't control her own behaviour. She'd have tantrums like a two-year-old, and then would hide to avoid being punished," Routh recounts.

Angela could barely read, and had difficulty interacting with other people.

"She was doing first things as a nine-year-old that we would regard as a normal way of life. She'd never been on a bus, ferry, she couldn't differentiate between a horse and a cow. She didn't have any toys and had never been to the beach or the pool."

Routh and Gilbo are one of a growing number of same-sex couples fostering children in Australia. In 2012, the Benevolent Society in NSW and Berry Street in Victoria actively started targeting LGBTI people as foster carers, seeing the community as a previously untapped source for loving homes.

This week, a children's book about a same-sex foster families was released, telling the story of Jesse, a young girl who goes to live with foster carers Tom and Jake.

Titled A Place in your Heart, the book is intended to give foster kids a chance to see and read about their own family situations.