Siblings Axel, Tommie and Henry Stevenson are one in 133,000.

Here’s one way to make it easier to remember your kids’ birthdays: have all three of them on the same day.

Lauren and Seth Stevenson of Dickinson in North Dakota have managed to do just that.

On September 1, 2014, Stevenson gave birth to the couple’s first child, Axel Lee.

On September 1, 2015, she had a little sister for Axel, Tommie Lee.

On September 1 this year, along came Henry Lee.

Stevenson says Henry was due on September 4, but she went into labour three days before that.

“It didn’t hit my husband and I until we were at the hospital that, ‘Oh my goodness, Henry is going to be born on the 1st like our other two’,” she told TODAY Parents. “We didn’t plan this at all.”

The likelihood of having all three children in the same family with the same birthday is pretty small: one in 133,000 or so.

But what makes the Stevenson case even more of a rare occurrence is that the babies were born three years in a row.

Stevenson’s obstetrician, Dr William Lowe, thinks it’s pretty amazing.

“The situation of babies being born one year apart for three consecutive years is that generally people do not get pregnant that quickly in order to be at due date by the next year,” he said.

The Stevenson family with their obstetrician, Dr William Lowe. Photo via KFYRTV.

Stevenson was working as a pump technician in the oil industry when she met her future husband.

She delivered a pump and he helped her unload it off the truck.

Their romance moved quickly, and they married, not long after meeting, in 2013.

“We dated for three months, we were engaged for three days, and now we have three kids born three years in a row," she said.

So far, the 23-year-old doesn't seem overwhelmed by parenthood.

“I enjoy it, it's fun,” she says. “The house is always busy, and there are toys everywhere.”

Two-year-old Axel is already helping to feed and bathe his little brother.

Mum and new bub. Photo courtesy KFYRTV.

Stevenson plans to go back to being a pump technician once she's spent a bit of time with her kids.

"I have a really good job and I'd like to keep it," she told The Dickinson Press.

She says she'd like to have one more child, but it won't be on September 1 next year.

"I think we're going to give ourselves a little of a break so we can watch our kids grow for a few years, and then maybe go from there."

As for birthdays, well, they haven't been too much fun so far for Axel and Tommie. They've both spent their special day in hospital rooms. But Stevenson says next year will be different.

"We're just going to have one big party, one big bounce house, give each of them a separate cake and their own presents."

Do you know of any strange coincidences with family birthdays?