Duggar fans have come to accept a certain level of creepiness from their favorite TV family.

The infamous Duggar courtship rules, the bizarrely strict dress code, the parents' constant meddling in the private lives of their adult children -- all of these have come to be tolerated, even by fans who would never inflict such intrusions upon their own offspring.

But a new revelation about the Duggars' surveillance practices may prove to be too much for all but the most diehard defenders to accept.

During a livesteam event sponsored by the Institute of Basic Life Principles -- the organization that provided the foundation for some of the Duggars' most bizarre beliefs -- Jim Bob and Michelle reportedly admitted to monitoring their adult children's cell phone use.

Michelle and Jim Bob revealed that they use Covenant Eyes, an "internet accountability software" program which enables them to monitor all activity on their kids' cell phones and computers.

The couple happily admitted that their adult children are subjected to this level of scrutiny, as well.

The practice continues as long as a Duggar child lives at home with their parents, which they are required to do until they get married and start families of their own.

Obviously, the implications of this are appalling.

Critics were quick to point out that 30-year-old Jana Duggar remains unmarried and still lives at home.

So it's safe to assume that this grown woman has never had a private conversation on a cell phone, either through talk or text.

According to those involved with the livestream, Jim Bob and Michelle appeared to see nothing wrong with the fact that Jana can't even send an email without her parents scanning it for inappropriate content.

The couple apparently did not go into specifics about what exactly they're looking for during these intrusions.

But those who are familiar with the Duggars' belief system know that the ultimate goal is sexual repression.

Jim Bob and Michelle have preached two seemingly contradictory ideas throughout their children's lives: procreation is the end-all, be-all of human existence; and sex is an inherently sinful act.

And so, once their kids reach sexual maturity, the parents go to great lengths to ensure that any and all sexual activity takes place within the confines of marriage and is strictly for procreative purposes.

We've known for years about the chaperoned dates, and the restrictions on all forms of physical contact that the Duggars use to police their children's involvement with the opposite sex.

But only this week did the Duggars reveal that their kids aren't even allowed to engage in a private telephone conversation.

In recent months, fans have observed that some of the adult daughters in the family seem to be in a state of open rebellion against Jim Bob.

It's even been rumored that Jill Duggar has cut off contact, and Jinger Duggar has been disowned by her parents.

If that's the case, it could be that they're lashing out against the man who oppressed them in their youth -- and trying to secure a modicum of freedom for their sisters who are still under his control.

View Slideshow: Duggar Family: Secrets of Their Twisted Ministry Revealed