"It's really special. Not many people get to graduate with their sibling," Anna said.
"We've had a great time going through medical school together."
Graduation will be a special family day.
When they receive their MB ChB degrees today, they will be among more than 560 graduands who will graduate in person from the University of Otago with degrees and diplomas in health sciences at a 3pm ceremony at the Dunedin Town Hall.
"I'm really proud of my sister and hopefully the feeling is mutual," John said.
When fellow students realised they were siblings and both studying medicine in the same year, the most frequently asked questions were: "Are you twins?" and "Is there another doctor in the family?"
The answers were, respectively, "No" and "No". John is 26 and his sister 24. They attended different Christchurch high schools. He completed a BSc in pharmacology at Otago, before beginning MB ChB studies.
And neither parent is a doctor. Their mother, Liz Mulholland, is a Christchurch primary school teacher and their father, Denis Mulholland, is a tour bus driver.
Both parents will be at today's graduation ceremony, and they will all go out to dinner together tonight.
"It's a very challenging career. You're always learning and I suppose it's the element of helping people that's really rewarding," Anna said.
One of the job's satisfactions was "making people happier in their lives", John said.
Having only recently completed their medical studies, both have now taken up house surgeon jobs, he at Hutt Hospital, Wellington, and she at Hawkes Bay Hospital, Hastings.
Although they spent two years going through medical school at the same time in Dunedin, they each had their own circles of friends.
And they have been at different Otago clinical schools over the past three years, she at the university's Christchurch campus and he in Wellington.
"We'd go home for the holidays [in Christchurch] and we didn't need to ask about things because we'd already know what we had been doing," John said.
They had always supported each other and she found found it was handy, during her early university studies, to have an older brother who was already experienced in university exams.
He had pointed out that, as well as swotting, it was also good "to chill out a bit", and to lead a "balanced life," Anna said.
