“What makes this case even more rare, is that my husband and I only had intercourse one time – his sperm stayed alive for 10 days to fertilise the second egg released.”

Kate’s obstetrician, Dr. Brad Armstrong, from Greenslopes Private Hospital in Brisbane, said he hasn’t seen anything like this. “I could not find any literature in the medical review websites at all.”

“I had to go and Google it,” he added. 

Kate and Olivia were initially given separate due dates, December 20 and December 30, however they were both born via planned cesarean section two days prior.