How Far-Fetched Is This Taboo Relationship In A Simple Favor?

Warning: The story below contains spoilers for the new movie, A Simple Favor.

The much-anticipated Paul Feig thriller, A Simple Favor, premiered last Friday, and there's a lot of buzz and intrigue around the film's plot. Based on a novel by Darcey Bell, the movie involves a lot of scandalous themes that make Gossip Girl look tame. One particularly racy topic? Incest.

Here's what happens in the film: Shortly after Anna Kendrick's character, Stephanie, loses her father, she learns she has a half-brother, named Chris (played by Dustin Milligan). Immediately, they're very attracted to each other, and they start hooking up in secret.

Their relationship goes on for several years, and continues after Stephanie gets married and has a child. Eventually, Stephanie's husband Davis (played by Eric Johnson) catches on to their relationship, and it causes a rift in their marriage. Emily (played by Blake Lively), Stephanie's best friend, finds out this information and uses it to manipulate her, even calling her a "brother-fucker."

This is definitely not the first time that a fictional film, book or TV show has depicted incest. From Game of Thrones to Riverdale, incest is pretty much a Hollywood cliché. On paper, Stephanie and Chris consent to a sexual relationship, and have a deep emotional connection. They are part of each other's lives as family and as partners, and care for one another. But how realistic is this on-screen relationship?

According to Robert Weiss, MSW, CSAT-S, a therapist who works with people with sexual disorders, "the scenario described is very implausible." For starters, incest is defined as any sexual contact between family members, according to the Rape, Abuse, Incest & National Network (RAINN). Incest can occur between parents or grandparents and children, cousins, aunts, uncles, nieces, nephews and siblings. But situations of incest between parents and children tend to be very different from sibling incest, because there is an imbalance of power between a child and adult. Most instances of brother-sister incest, like in the film, tend to occur in large families where there is a lot of trauma, he tells Refinery29. If the parents are abusive or neglectful, "the kids turn to each other for support and love, which becomes sexual," he says.

It's very unusual for older teens and grown adults to begin a consensual incestuous relationship, Weiss says. "This doesn't happen in everyday life," he says about the way Chris and Stephanie get together as young adults. Often, incestuous behavior starts when siblings are young children, but then stops when they reach a certain age. "There's usually a long-term relationship between the siblings and [it's] something that evolved out of the traumatic environment they're living in," he says. "It sort of becomes a mutual way of surviving this difficult environment."

For most, incest is a really tricky concept to understand. Emily Nagoski, PhD, sex educator and author, wrote about what drives people to act on incestuous thoughts on Medium. Basically, some people are able to act on a consensual incestuous desire, because "for whatever reason, [their] brain didn't learn to activate in response to that sexually relevant information, or else the context is sufficiently activating to overwhelm the brakes," she wrote.

And, incest isn't just taboo, it's also illegal in many states in the U.S., which is why people usually keep incestuous relationships secretive. Unfortunately, sexual abuse that occurs within families is often mischaracterized as "incest." This can make it challenging for survivors of familial sexual abuse to recognize and report the behavior. "It can be difficult for someone to disclose sexual assault or abuse when they know the perpetrator, especially if the perpetrator is a family member," a representative for RAINN tells Refinery29. "The survivor may care about the abuser, be concerned with their family's reaction, or fear they won't be believed." Nonconsensual sibling incest can have long-lasting emotional effects, so it's important to take it seriously.

The type of incest depicted in A Simple Favor doesn't fit these typical molds. Viewers are supposed to believe that Stephanie and Chris are two adults who chose to be in a relationship — but why? Yes, it's a major plot driver, as Stephanie ends up being blackmailed with this information, but surely the book and film adaptation could have come up with a more realistic reason. Maybe it's to make Stephanie appear complex, maybe it's simply for shock value, since incest is one of the most controversial types of consensual relationships that anyone can ever enter. But on top of all the other shockers in the movie, the incest element really wasn't necessary; it ends up being just another ridiculous aspect of A Simple Favor's storyline, one that doesn't add any real emotional or narrative value to the plot, and probably wouldn't happen IRL.