The identical twin sisters are pretty much as inseparable as two adult siblings can get. They teach at the same school, married a set of "best friends," live down the street from each other and talk to each other about "50 times [a] day." To say they have a lot in common is obviously an understatement since, as identical twins, they share most of their genetic code, after all.
More: Touching sonogram shows unmistakable bond between twins (VIDEO)
But these two ladies took it to the next level with their kids. They each gave birth to a pair of twins through IVF in 2010 and 2011, 11 months apart from each other. Now they've given birth to a second set each, Wall through IVF and Bunker au naturel, just three weeks apart from each other.
In between the two twinstravaganzas, Bunker conceived and gave birth to a singleton daughter, which brings the total number of children between the two up to nine. They're all under 5, which means that if nothing else, the next decade should be more than eventful.
Statistically it isn't surprising that either woman would have twins. They both used IVF, and they're both considered to be just this side of "advanced maternal age." The only thing that actually didn't play a factor in their twincidents is the fact that they are themselves twins.
More: Dad has good reason for wanting to tattoo his baby
See, the chances of having twins for singletons is 1 in about 250 pregnancies. The odds of having a twin when you are an identical twin is the same — 1 in 250. Now, if you are a fraternal twin, your chances of having twins skyrockets to 1 in 35.
Even then, that's only if you yourself are the twin. Dizygotic or fraternal twinning appears to be passed through the maternal line, which means if Dad's a twin, that's great for cute videos but inconsequential to having more twins.
The women are identical twns, so their chances of having twins would have been the same as anyone else's, just boosted a little by the IVF. Where the statistics start to get particularly interesting is when you take the odds of having a second set of twins after giving birth to one set. If the first set is fraternal, your next pregnancy is four times more likely to also be with fraternal twins. So statistically speaking, having twins for a second time isn't the amazing part. The first twin pregnancies were less likely to happen. Confused yet?
With Bunker, though, that statistical tangle meant very little. She started IVF because she was facing fertility challenges. Her doctor called her chances of having any children naturally "so low she was practically barren." Which makes the following anecdote about the sisters' second tandem pregnancies so much more incredible. According to KUTV, it all started when Wall called her sister to share the news that she was having twins again:
The day Wall told Bunker she was pregnant with twins, a random thought popped into her head.
"I got this hair-brained idea that, what if I was pregnant?" said Bunker.
That day, she found an old pregnancy test and took it.
"I don't even know what made me think I could be. There was nothing, I mean nothing. And it was just why not? And I found out I was pregnant the day she found out she was having twins.
More: 'Rainbow baby' photo captures beauty after heartbreak
Man, that's so freaky.
But in the best possible way, of course. The sisters are now doing what any logical twin mother of multiple twins would do if she was tight with her own twin: moving in next door to each other.
All of their children will grow up pretty much the same way as siblings would, which makes sense when you consider this last little twin factoid: The children of identical twins (for instance, all nine of the Bunker-Wall clan) are genetically half siblings, not cousins.
Whew. It's OK if you need a second to process all of this. Our heads are still spinning.