An Australian mother has welcomed healthy conjoined twin daughters with one body and two brains despite doctors’ suggestions to terminate the pregnancy.

On Thursday last week, Renee Young and her partner Simon Howie, from Sydney’s west, welcomed babies Faith and Hope six weeks before their predicted due date.

The couple, already parents to seven other children, learned that the twins were in fact sharing one body in an ultrasound.

Faith and Hope have the same body, heart and skull, but have separate faces.

Twin sisters Faith and Hope.

The condition, known as diprosopus, has only 35 other documented cases and a zero per cent survival rate.

Doctors warned the parents that the rare babies may not survive the birth, but they decided to proceed.

“The physical structures in the chest are probably consistent with a single person, but how the neurology works and how the brain is connected – that is really hard to determine whether they will function normally,” Maternal foetal medicine specialist Dr Glenn Gardener told the Herald Sun.

“I think one of the biggest risks to this baby, in terms of surviving, is its ability to breathe on its own,” Maternal foetal specialist Dr Greg Kesby said.

However, the parents remain hopeful.

“They are breathing perfectly on their own and feeding. They even had their first bath last night,” Mr Howie told A Current Affair.

“I would say if I only get two days with the baby, at least I have some time with it,” Ms Young said.