It's impossible to enter into a discussion about the Duggar family without mentioning the very particular set of religious beliefs and customs that dominate most of their waking hours.
The family's ultra-conservative views have been a top focal point for both fans and critics, with the former praising the Duggars for their piety, and the latter condemning them for their archaic views.
The Duggars have their religion to thank for their continued fame, but it's also been the source of some of their most damaging scandals.
Almost two-thirds of Americans identify as Christians, but very few of them would feel at home in one of the Duggars' church services.
Even fellow believers in the Duggars' minuscule sect would likely balk at the prospect of raising their children as strictly as Jim Bob and Michelle have.
Their probable reasons for granting their own kids a longer leash would be fully supported by the Duggars' current set of circumstances.
It stands to reason that if you use your faith to justify controlling every aspect of your children's lives, they're far more likely to rebel at the first opportunity.
And that's exactly how the Duggars wound up in their current crisis -- one that's created an endless string of tabloid-friendly controversies and some deep divisions between parents and kids.
But before we attempt to determine whether any of the Duggar children have gone so far as to leave the church, we have to answer a more fundamental question.
Namely -- what religion are the Duggars?
The answer is not as simple as you might think.
The Duggars are Independent Baptists -- a fairly sizable sect that comprises roughly 2.5 percent of the US population, according to a study by the Pew Research Center.
Independent Baptists have a long history of far-right conservatism, having been founded by a small contingent who felt that more mainstream Baptist sects were becoming too liberal.
The Duggars, however, didn't feel that the IB branch is conservative or insular enough on its own.
And so, they joined the Quiverfull movement.
The brainchild of Institute for Basic Life Principles founder Bill Gothard, the Quiverfull movement lost most of its members when Gothard was forced to step down amid a string of sex scandals.
But Jim Bob and Michelle have remained faithful members -- and so, it seems, have most of their kids.
The IBLP and the Quiverfull movement teach that it's the duty of every Christian woman to give birth to as many children as possible.
That's why there's pretty much always a pregnant Duggar.
Just this week, we learned that Jessa Duggar is expecting her fourth child.
At just 28 years old, Jessa seems to be planning on raising a double-digit-sized brood.
So it's safe to assume that she's still a believer in both the IBLP and the teachings of the disgraced Bill Gothard.
Her older sister, however, seems to have chosen a very different path.
Jill Duggar is no longer on speaking terms with her parents, and she seems to have little interest in following their belief system.
In recent months we learned that Jill drinks alcohol and uses birth control, both of which are major no-nos in the Duggars' world.
She almost certainly practices some sort of evanglical faith, but odds are, she's abandoned the Quiverfull movement and no longer attends services at an Independent Baptist church.
The other most likely candidate for defection is Jinger Duggar.
Jinger lives in Los Angeles with her husband, Jeremy Vuolo, who is currently studying at a local divinity school.
The Vuolos are Baptists, but they've abandoned many of the rules that define the Quiverfull lifestyle, including the one that requires women to wear long skirts at all times.
So Jinger has forged her own path (with the permission of her husband), but it currently looks as though she and Jill are currently the family's only rebels.
We can only hope that some of their siblings will see the light as they gain more experience of the world.