John David Duggar, the family's second-oldest son, keeps a fairly low profile compared to his more famous siblings.
The reason for this has often been the subject of debate.
Unlike so many of his brothers and sisters - including his twin, Jana Duggar - John David seems relatively uninterested in the reality TV spotlight.
The presumption among card-carrying members of Duggar Nation has always been that the 28-year-old simply has other ventures to pursue.
John David is a pilot; he does construction and maintenance work on properties owned by his father, and he volunteers with his local police and fire departments.
Without question, the man has a very busy schedule.
But it seems that's not the only reason that he takes a dim view of his parents' unquenchable thirst for fame.
According to a former employee of the Duggar family who spoke to The Hollywood Gossip exclusively, he just doesn't approve.
Indeed, while we may not always see it on camera, John David has emerged as his family's moral compass in recent years.
Which means that when John David seems to be distancing himself from his parents, it's not something to be taken lightly.
Fans who are drawn to the Duggars' supposedly wholesome lifestyle and family values should pay close attention.
"When John David doesn't want to be a part of it, then you know that it ain't right," says the insider.
"John David is a good guy, and he's in a good spot."
"He gets to do what he wants to do."
And apparently, he wants to do these days is keep a safe distance between himself and some of his father's worldly impulses.
"There's things that Jim Bob does that John doesn't think are right," our source tells us of the friction between the two men.
"Some of his real estate transactions, some of the equipment that he buys - a lot of this stuff, Jim Bob doesn't really need, but he thinks he does."
In the past, we've reported on allegations that Jim Bob is a "high-class hoarder" who is secretly reckless with his finances.
Now, it seems John David has taken issue with his father's profligate ways, and not only because they conflict with the Duggars' Christian values.
There is also increasing concern that Jim Bob's constant consumption is threatening to bury the family in debt.
Says our source:
"He'll go to an auction and he'll come home with a bucket truck that he got for $4,000, then he'll realize that it needs $8,000 worth of stuff to fix it."
"And John, he gets kind of tired of that."
"There's a lot of stuff that Jim Bob does that John doesn't agree with, but now that John's up and in the world, that's his right."
And it seems the conflict between father and son goes beyond financial matters and into the Freudian realm.
That's right, patriarch and father of 19 Jim Bob is beginning to see John David as a threat to his familial dominance.
"[John David] is old enough now that he can pick and choose what he wants to do, and that just kills Jim Bob," our insider says.
"Because he doesn't have that ultimate control."
"He's losing his control factor," he adds.
"He's got control over the little ones while they're there, but he realizes that soon they'll be big and gone, and he'll lose that."
Concluding on a note of levity, our source jokes: "And then he'll have to deal with Michelle on a full-time basis!"
Gonna be rough.