"It's unplanned that's for sure, I'm a bit lucky really," Mr Sharp, 32, said. "It sure beats socks and undies. I don't think I'll throw the wrapper away just yet," he joked.
But not only have they given birth to two children on Father's Day their oldest child, Harrison, 6, was born on Halloween - October 31.
"It's pretty safe, eh, I can't forget them now," Mr Sharp quipped.
He recalled that while having dinner with family last night for a joke he went and got the "grab bag" for the hospital and put it by the front door.
"Brad decided that [the baby] was coming last night so he put the bags at the front door," Mrs Sharp said.
Her husband said it turned out to be "quite convenient".
Although their baby had been due today, the couple were still shocked when Mrs Sharp started having contractions.
"I came to and got the sleep out of my eyes and was, 'oh really, again? Good timing honey'," he joked. "Oh, you couldn't wish much more for a Father's Day present. It's pretty cool."
The couple, who live in Te Awamutu, live just down the road from the town's new birthing unit which was due to open on September 1. However, due to council delays the doors are yet to open. "We're up the hill from the new birthing centre but it's not open yet...we were hoping to just roll down the hill."
As for having any more kids, the couple aren't so keen.
"The back seat's full," Mr Sharp said.
"And I don't want a people-mover," Mrs Sharp added.
The couple's midwife said research showed that only between 3 and 5 per cent of babies were born on their due date.
