These extraordinary identical twins were born a minute apart but one is three times bigger than the other.
Byron Ryman weighed in at 3lb 6oz, followed by his brother Lincoln at only 1lb 2oz when they were induced 11 weeks early.
Doctors had given Lincoln only a one-in-three chance of survival because he was so small. However, since his birth on March 25 he has shown a remarkable will to live.
He underwent one operation to overcome heart and breathing problems when he still weighed no more than half a bag of sugar.
The twins have also managed to put on weight with Byron gaining 2lb 3oz and Lincoln 10oz since they were born.
The boys’ parents, Nicole and Todd Ryman, 32, who conceived through IVF, admit their first weeks of parenthood have been nerve-racking.
“We’ve been on top of the world because we didn’t think we were going to have them both,” said Mrs Ryman, 31.
“We’ve had a few scares along the way but they’re pretty well going forward now and I know I’m going to be able to take them home.
“During the pregnancy the doctors would write Lincoln off. It was touch and go at times. But he’s a big boy now. They’re both fighters.”
Dr Parag Mishra, who is looking after both infants at the Royal Hospital for Women in Sydney, says he is delighted with their progress. While Lincoln is expected to spend the next four to six weeks being cared for in the newborn intensive care unit, Byron is likely to leave hospital at the end of next week - just in time for Mother’s Day in Australia.
Dr Mishra, who monitored Mrs Ryman’s pregnancy, said he had been forced to prepare her for the worst.
“Nicole was 15 weeks along when medical staff detected twin-to-twin transfusion, a type of problem whereby blood flows from one twin to another,” he said.
“At 29 weeks, we realised Byron’s growth had completely stopped, so it was decided that we would induce her to give him a good chance of living.
“Lincoln had some hope, but the chance of survival I gave was less than 30 per cent because he was so small.”
However, both brothers showed an exceptional will to live.
“When they came out, they both had problems - Byron needed a little bit of help breathing, but then subsequently gained proper weight and was going well,” the doctor said.
“Lincoln initially had a lot of breathing problems and then he had a lot heart problems, so an operation was done while he was still about 500g.
“Hopefully he’ll soon start gaining weight much more quickly and get nearer and nearer his brother.”