Joanna and Chip Gaines of “Fixer Upper” on HGTV. (Brian Ach/Invision/AP)

This story is by Kate Shellnutt, a journalist covering faith and pop culture.

Chip and Joanna Gaines, the smiley, shiplap-loving couple at the center of HGTV’s “Fixer Upper,” have hit another milestone in their reality TV careers.

Days after their latest season premiere broke records on cable, and a few weeks after their first book topped the New York Times bestseller list, online outlets challenged their evangelical church’s stance against same-sex marriage.

As the proud Baylor University grads go from everyday people to household names, they join a cast of reality TV families known — and scrutinized — for the values they represent. The discussions around the Gaineses and their beliefs reveal how great a role reality TV plays in how Americans think about marriage, family and sexuality.

“Reality TV comprises a new chapter in television’s history as a domestic medium that has always focused on the family,” wrote Leigh H. Edwards in “The Triumph of Reality TV: The Revolution in American Television.” “Pundits, politicians, media critics, and psychologists alike have insisted that television helps define the modern family and contributes to that social unit’s evolution or decline.”

American viewers share a familiar critique of this genre that it seems cliche to repeat it: Reality TV is not “real” at all, they insist. Although series like “The Hills” and “Real Housewives” amp up the drama with constructed scenes and scripted lines, even the milder fare on HGTV is not exempt from illusion.

Discovering that “House Hunters” is staged — that the couples have already selected their home before shooting — is the closest thing in my adult life to finding out the truth about Santa.

Yet, for all the caveats of production, fans recognize reality TV stars as real people in real relationships. It’s why people trust Chip and Joanna Gaines’s playful banter and gentle Texas accents … and it’s why they are concerned about what they say, do and believe, even off-screen. Their relentlessly cheery rapport was enough to cause one evangelical site to run an article praising them as a model for joyful Christian relationships, while another news warned, “Don’t Let Chip And Joanna Gaines Destroy Your Marriage.”

So, yes, people care.

Controversies over sexuality and same-sex marriage have emerged within a subgenre of Christian-fronted reality TV shows in recent years, most famously involving the Robertsons of A&E’s “Duck Dynasty.” Their program was the network’s breakout hit (not to mention merchandising machine) two years ago when grandfather Phil Robertson came under fire from fans and A&E itself for his characterization of “homosexual behavior” in a GQ article.

Then in 2014, HGTV pulled a house-flipping show starring two brothers who went to Liberty University and were vocal opponents to same-sex marriage.

“Reality TV, at its best, gives rise to significant social backlashes, often at odds with the original intentions of the producers,” noted Stephen Coleman, another author and scholar. In other words: The controversies around our favorite shows remind us that reality TV can indeed get real.

But there have been quieter examples as well. The messy string of reality-TV-star splits (think “Jon and Kate Plus Eight”) can seem to confirm the shakiness of marriage in the 21st century, while the subgenre of over-the-top bridal shows (“Say Yes to the Dress”) perpetuates traditional norms. The popularity of “Teen Mom” and “16 and Pregnant” have been linked to a drop in teen birthrates. And for decades, reality TV has been a place where gay couples and families enjoyed better representation and fewer stereotypes than other forms of entertainment.

“This goes back to ‘Trading Spaces’ [in 2000]. ‘Trading Spaces’ and all these HGTV shows have had gay couples before scripted television had very many of them,” said NPR pop culture correspondent Linda Holmes on a podcast earlier this year. “While there may be sometimes the woman and her ‘friend’ Fran, there are also quite a lot with an out gay couple. They were doing that … relatively regularly and frequently.”

Although politicians and denominational leaders weighed and debated LGBT issues in recent years, some overlooked how the issue kept seeping into the ever-expanding network of reality TV shows. I wonder if Caitlyn Jenner would have become such a high-profile, influential transgender icon had she not been in the public eye as Bruce Jenner on “Keeping Up With the Kardashians.”

Of course, the Kardashians are one of the most divisive families in reality TV — so famous you either love them or hate them — but some of the biggest names in “family values” reality programming haven’t fared much better in the tabloids.

TLC canceled “19 Kids and Counting” last year, after news reports on Josh Duggar’s molestation of his sisters as a teen and sexual exploits while married to his wife. Earlier this fall, People magazine reported that the patriarch of the Duggars’ slightly smaller, 14-member successor, “The Willis Family,” was arrested on child-rape charges.

A Daily Beast column pointed out that such shows were supposed to be more wholesome options than the rest of reality TV, but they have not had a good track record:

“They arrived as both antidotes and counterprogramming to the vapid debauchery on franchises like ‘Real Housewives’ and ‘Jersey Shore.’ Those shows celebrated Botox, Jaeger shots, and catfights. These series trumpeted the importance of family, religion and love. Reality TV was shifting from the godless to the godly, and the ratings were so good they were practically heaven-sent. But look at what has come in the wake of their ascension.”

There are enough evangelicals on reality TV that it has become a semiregular beat of mine as an editor at Christianity Today. The lessons we learn from these reality TV families center more around their own relational dynamics than the conceit of their shows.

I never watched “19 Kids and Counting” to learn the home economics of feeding a crowd or DIY perms, and like many “Fixer Upper” fans, I will never embark on a home renovation project, no matter how “easy” Chip and Jojo make it seem. As Edwards writes, even when reality TV doesn’t explicitly or critically engage the social dynamics we see shifting around us, it lets us “peer into other people’s households to see how all this cultural ruckus is affecting actual families.”

The election of former “Apprentice” host Donald Trump to the presidency led many Americans to note how reality TV was making its way into the political world. But when it comes to marriage and family, culture-war politics have been a part of reality TV all along.

Kate Shellnutt works as an editor at Christianity Today magazine.