Inside ‘Biosphere’s Wild Twist: Stars on Navigating Gender Conversations — And Why You Shouldn’t Compare It To ‘Junior’

Spoilers for Biosphere past this point. 

The sci-fi dramedy Biosphere refuses to give viewers an opportunity to back out before its unpredictable twist takes over — and that’s intentional. What starts off as a buddy flick about two friends navigating life in a geodesic dome after surviving an apocalyptic event transforms into a WTF masterpiece brought to life through magical realism, magnetic chemistry, thoughtful meditations on masculinity, and male pregnancy. Yes, you read that right. 

At the beginning of the movie, Billy (Mark Duplass) and Ray (Sterling K. Brown) reveal that their lifestyle is being sustained by a tank of fish, and their last female fish has died. Stuck with only males, the fish are no longer able to reproduce. Suddenly, a male fish begins sporting a few oddities. Ray, who is a scientist, takes a closer look and discovers that the fish is undergoing an accelerated form of evolution.

Reduced to an elementary-level description, this aspect of evolution sees living organisms adjusting to their environment for survival. And while it’s nothing new – unless you live under a rock or are part of a religious cult – this movie universe takes it to another level.

The male fish have seemingly realized that they will cease to exist without a female fish, therefore one of the male fishes has adapted its biological sex organs to emulate a female fish and solve the problem at hand. In the wildest movie twist of the year, Biosphere applies that same logic to its friendly male duo. 

Decider spoke with director and co-writer Mel Eslyn along with Mark Duplass and Sterling K. Brown about the movie’s venture into this uncharted film territory, which hasn’t really been explored outside of the realms of fanfiction and the 1994 comedy Junior. Eslyn, for her part, refused to be compared to the previous iterations, saying they had always dealt with male pregnancy as “a joke or a punchline,” noting that Junior, in particular, lacked sensitivity. Instead, Eslyn approached the subject matter “with thoughtfulness and heart, and hoping to expand people’s minds — that every type of body and human can be defined however you like.”

In order to tackle the subject manner, Eslyn talked to a diverse team of trans women, queer women, and non-binary folks to help guide the movie. One big question surrounded whether Duplass, who co-wrote the movie, should take on the role of Billy, as the character grows female sex organs throughout the movie and laments about losing his dick – until he embraces his body and is overcome with new urges that see him vying for physical touch and a baby. Ultimately, Eslyn felt as though Duplass, or a similar straight, cis-male needed to play the role in order to reach their desired audience.

It wasn’t a long search, though: Duplass’s involvement was a bit of a no-brainer given that the movie was produced by Duplass Productions, of which Eslyn is the president. She shared that either Mark or Jay Duplass always stands as a “prototype for a character” during the pre-production process of their films, and sometimes they carry the character through to the final product and sometimes they don’t. In this case, Duplass did. The bigger shock was getting Brown to agree to play Ray. “I did always write with Mark in mind and Sterling as well, but I didn’t think we were going to get Sterling,” Eslyn said. “We were like, ‘We just gotta try,’ and this never ever happens, but we sent it to him and then the next morning he Zoomed us and said ‘I’m in,’ and that was it.”

Upon first reading the script, Brown felt like the movie was “a big swing,” but he was drawn to the role because “no one will mistake this character for Randall,” referring to his character in the NBC drama This Is Us. More importantly, he felt connected to the themes. “I committed myself because I thought the story was important enough about tolerance, about acceptance, about loving people, and it’s something that I stand for very much.” He recalled giving himself a pep talk, saying, “Alright, Brown. Now it’s time to inhabit that space of love, and see how you show up for it… It wasn’t the big deal that I thought it was going to be.”

With the actors in place, the question became how much Duplass’s body needed to change throughout the 106-minute runtime. “I never wanted to give anybody who doesn’t understand the sensitivities [of] the space to turn it into what it isn’t,” Eslyn explained. “We all have different bodies. Who’s to say what the female body looks like? So, it wasn’t about fitting any sort of stereotype. It was just a bit of a physical transformation, but more emotional.” Thus giving way to the blink-and-you-miss-it changes, which come to a head once Billy becomes pregnant in the final act. 

References to Billy’s body throughout the movie include his growing breasts and shrinking male organs. Throughout the process, Billy falls into a deep depression, and he and Ray decide to have a funeral for his penis. “I know that it wasn’t always in the perfect direction, but I think that you had our best interests in mind,” he says to the makeshift, presumably empty coffin. “I think … actually, I don’t know if that’s true. I’m really confused,” he admits and breaks down.

As the movie progresses, Ray and Billy find themselves growing apart due to the elephant in the room. At one point, Ray sports a hard-on after noticing Billy’s newly developed breasts, and the two fall into an awkward dance of sorts until Billy starts a conversation about the changes. He admits that he’s gotten his period and wants to further explore his body, perhaps with Ray. His friend is turned off by the idea and the two have an explosive argument. Ray ends up saying a homophobic slur in regard to their relationship before storming off. Later, he explains that he is having a hard time navigating his feelings because of his upbringing where he was taught, “A man was a man with a very narrow, rigid definition of what that meant, with no room to vary.”

Eslyn feels that this scene, in particular, is the most important in the movie when it comes to establishing their relationship, rather than the several “will-they-won’t-they” moments or the jaw-dropping sex scene, which sees the two having sex “as friends” … for science… before engaging in a passionate kiss. “That moment was one of the most important… because it was them bringing their vulnerabilities and their faults to the table. They were both complicit in decisions that they blame the other for.”

Duplass appreciates the movie’s approach to these vulnerable conversations, which challenges the absence of intimacy in male friendships. “There’s a consistent element of my work, which is [that] I’m constantly trying to burrow as closely as I possibly can, in this world, to the people that I love,” he said. “Then, I find myself very quickly, either overstepping their boundaries or forgetting my own boundaries, and realizing we need our own personal space. That balance is impossible for me to find. This movie was an opportunity for me to do that.”

He added, “In a way [Biosphere] is a fatalist version of that. It is much more hyperbolically comedic and with story points that are wildly outside of the realm of what we consider normal. That was very new for me – to do something that was in the realm of sort of magical realism, but with very, very real things that I think about all the time.”

To bring Billy and Ray’s tender relationship to life, Duplass looked towards his relationship with his brother for inspiration. “Things that I’ve made tend to veer towards male intimacy because it’s something I’m really interested in. I think it’s because of how close I am with my brother – we have a wonderful relationship. When I look at Biosphere, I think it’s in some ways, the ultimate way to pressure cook that intimacy. There’s no escape for these guys.” Brown, on the other hand, has a group of “cis-gendered, heterosexual” friends whom he cannot imagine his life without. And while it’s Billy who undergoes the crucial physical transformation during the movie, Eslyn believes Ray “transforms just as much, if not more by the end” through their experience. “They’ve been in there long enough and now they’re forced to confront conversations they’ve never been forced to have before,” the writer noted.

Biosphere concludes with an ambiguous ending that circles back to the beginning of the movie and emphasizes the beautiful ride-or-die relationship the two characters have cultivated through a lifetime of knowing one another. Without giving too much away as to what the final scene signifies, Eslyn hopes that audiences ” take away a feeling of the beauty of hope.” She wants people to acknowledge that “not understanding is okay.”

The gender switch, male pregnancy, and bold shockers that Biosphere intertwines in its plot aren’t the result of a big jokey conversation or fanfiction-esque dream. Instead, it simply is what it is. The movie works because of Eslyn and Duplass’s high-quality writing and their thoughtful consideration when it comes to addressing these sensitive topics. And while seeing Duplass and Sterling smooch may make you giggle (and that’s okay!), if you dare to look beyond the surface, you will see that Billy and Ray’s relationship is greater than what meets the eye — and so is Billy’s gender transformation.

Biosphere is currently out in theaters and on VOD.