The baby was born in May, but doctors are still trying to identify its twin, a baby with the first twin, according to the first ultrasound ever performed on a twin.
The twin is being kept at a medical unit in a Brisbane hospital for observation and possible diagnosis, according the Australian Broadcasting Corporation.
It was not immediately clear how many embryos were in the baby’s womb at the time of the scan.
It is not the first time twin pregnancies have been performed in Australia.
Two pregnancies in Victoria in 2009 led to the birth of twins.ABC News asked whether twin pregnancies were performed in the future, and the Health Minister, Greg Hunt, replied that the Government was working to address the twin issue.
“I am not going to speculate about future twin pregnancy investigations, but the Government is actively working to improve the health of twins and this is part of our ongoing efforts to do so,” he said.
“We have been working closely with the health department in Victoria and are committed to ensuring that twins do not occur at any stage of pregnancy.”
Dr Scott Friel, who led the study at the University of Queensland’s School of Ophthalmology, said it was a very rare occurrence.
“It is rare enough that it would be worth it,” he told AAP.
“Usually the twin is the result of a very close genetic connection, so the twin would be expected to be born with the identical DNA, but in this case, the twin had a different DNA.”
Dr Friel said it could be that the twins had been genetically linked for years.
“In this case there was some degree of genetic linkage between the twins, so if it was really a very recent genetic connection that had been shared for some time, that would be a very unusual case.”
He said the twin was in a very good state of health and appeared to be doing well, but it was still too early to say whether the baby was healthy or if the twin needed a second operation.
“The twin would require an operation and that is the next step,” he added.
“There are other ways of achieving twin pregnancy, for example a vaginal birth, but I think the only way that we can really be sure is to do an ultrasound.”