SIOUX CITY -- Matt and Lindsey Rixner are the parents of a seemingly improbable family: two sets of twins, both born in October.
Do twins run in their families? Sort of, but not really.
"My great-grandmother had three sets of twins," said Lindsey Rixner, a fifth-grade teacher at Liberty Elementary.
But that was on her father's side, and according to the research she's done, twin-bearing is passed along the mother's line.
So there isn't much of a genetic explanation for Stella and Sofie, born Oct. 22, 2015, and Lennon and Miles, born Oct. 26, 2018.
There is, however, a medical explanation for having more than one set of two: Matt and Lindsey are both 37.
"You're more likely to have twins in your 30s than you are in your 20s," Lindsey said. At that age, the female body feels a need to make use of its eggs. Thus the twins.
"Some women over the age of 30 tend to shoot out more eggs," said Matt, who works at local broadcaster KMEG.
Both Sofie and Stella and Lennon and Miles are fraternal twins, meaning they're like siblings born at separate times, only they were born at the same time.
Lindsey was 20 weeks along with the first pregnancy when they learned she was going to have twins.
"Big surprise, for sure," Matt said.
Stella, who is a minute younger than Sofie, was born with Down Syndrome and a stomach condition that left her in the neonatal ICU for more than a month. Her medical conditions presented a challenge for the Rixners, especially in her first weeks when she was very ill and underwent stomach surgeries.
"Most of the time you think about twins having the same developmental milestones, like crawling at the same time, walking at the same time," Lindsey said. Stella's milestones came about a year later than Sofie's.
"And that's OK. They're individuals," Lindsey said.
What's nice about them being twins, the Rixners said, is that Stella will always be able to look to Sofie as a sort of role model to learn from.
Sofie and Stella tend to wear the same outfits, making their appearance more twin-like. Miles, a boy, and Lennon, a girl, don't dress alike.
The Rixners said having four children so close in age comes with its peculiarities. You get less one-on-one time with each individual child when there are four of them to tend to.
"You don't get as much time to sit and snuggle, or hold them, because there's always someone else who needs to be changed or fed, so I think that's a challenge," Lindsey said.
Planning and keeping a schedule are also important for maintaining an orderly household with so many twins.
"It's all about routine, that's the biggest thing," Matt said. "You feed both of them at the same time. They sleep on the same schedule as much as possible."
The Rixners also make a point of leaving their house to go shopping or out to dinner when possible, rather than letting themselves become trapped inside the house. People definitely notice the big family.
"I think we kind of draw a lot of attention from people, if we're going to dinner or we're in the store pushing double strollers," Lindsey said. "We really draw a lot of attention."
Do the Rixners plan to further add to their already-sizable family?
"Nope," Matt said.
"I think statistically, the chances of us having twins a third time would go up" with any additional pregnancies, Lindsey said.