There's something self-reflexive, even ironic, about the title of writer-director Robbie Pickering's Natural Selection, and not just because the chief precept of Darwinism is entirely counter to the fundamentalist worldview of this film's protagonist. Pickering's debut feature opens with a quote from scripture informing us that to "spill your seed in vain" is indeed a sin and then introduces us to the living examples of devout-but-infertile Linda (Rachael Harris) and her husband Abe (John Diehl), a man who tucks his shirt into his tighty whiteys and sidesteps that biblical ordinance by making frequent (and covert) visits to the sperm bank. Immediately sympathetic where her spouse is mostly just uncouth, Linda is endearing even and especially as the strangeness of her situation puts her at a remove: This is a woman whose piety manifests itself in self-abnegation and utter lonesomeness. We get the sense early on that her faith is an impediment forced from without rather than a liberating force, a suspicion subtly enhanced by Harris throughout. She imbues her character—who even Pickering himself seems to be making fun of at certain points—with earnestness and warmth from the very start; that Natural Selection doesn't descend into condescension or sentimentality is owed almost entirely to her.
The early revelation that Abe has fathered at least one child through his tireless efforts at the sperm bank brings the title's implications into relief. The son in question is a lowlife, the kind whose position at the fore of this story immediately feels at odds with what we know of the faithful couple, and so we're forced to wonder who will rub off on whom. This is made more fascinating by the fact that it's largely subtextual and rarely belabored. There's a feeling here of oldness and, with it, the implication of both reliability and weakness, neither of which is entirely accurate with regards to Linda, and it's only as everyone else's longstanding conceptions of her erode that she comes into her own. Natural Selection works because what it documents is less a transformation and more a return to a former, more natural state for its troubled protagonist. Starting off as seeming opposites, she and the semi-stepson (Matt O'Leary) she endeavors to track down are immediately poised to bring out certain qualities in one another. The more Linda herself realizes this, the more isolated she becomes. Confronted with a host of uncomfortable realities, she tries and fails to turn away from the self even as she knows her only option is to eventually embrace it.
But the rest of the film leaves little to the imagination. The contrast between Linda and nearly every other character is sometimes too clear cut, even if her being too independent for the pious and too uptight for everybody else can be quite affecting. Little that Natural Selection offers is especially new or exciting, and as things progress its execution sometimes slows down to the level of its admittedly generic conception. Excusable grievances that start out as minor work their way to the front of the mind; conversations become redundant rather than revealing. But these shortcomings—a supporting cast that's ill-equipped to do much heavy lifting, a script that's more formulaic than it initially appears—are ultimately offset by a central performance as understated as it is powerful. Harris elevates the material in a way that cuts through its ugliness and leaves something truer, more genuine in its place. As the real Linda emerges, everything else once again recedes into the background—and rightfully so.