From Truman Capote biopics to Robin Hood adaptations to period magician mysteries, Hollywood is accustomed to films coming along in accidentally duelling pairs. Gay conversion therapy, however, is one of the unlikelier subjects we’ve seen for movie twinning: a grim, once-niche concern being dragged into the spotlight for mainstream shaming. We have yet to lay eyes on Boy Erased, Joel Edgerton’s adaptation of Garrard Conley’s memoir of being pushed into a gay conversion program by his fundamentalist Baptist father: with a November release date and an all-star cast running the gamut from Lucas Hedges to Nicole Kidman to queer-pop waif Troye Sivan, it’s the gloss-finish, awards-baiting half of the pair, as well as the one on which a frankly daunting proportion of the Gen-Z internet has its hopes pinned.

Before then, however, Desiree Akhavan’s The Miseducation of Cameron Post is slipping into cinemas with quieter advance fanfare. A casually wry, moving adaptation of Emily M Danforth’s 2012 novel – about a teenage girl drafted unwillingly into an abusive gay conversion camp in the mid-1990s – the film made some noise at the Sundance in January, where it surprised most pundits by taking the top honor, the grand jury prize, in the festival’s US narrative competition. (In a relatively under-reported statistic, it was one of four woman directed films to dominate the jury awards in that section.) Since that early success, however, The Miseducation of Cameron Post hasn’t received quite the red carpet rollout being afforded Edgerton’s film (or, for that matter, such past Sundance champs as Whiplash or Precious). Reviews have been warm if not, for the most part, ecstatic; already, the industry appears to be shaping it as a respectable mood-setter for Edgerton’s bigger, shinier effort.

Boy Erased may turn out to be brilliant, but Akhavan’s film is not to be slept on. Forthright and unsentimental in its emotional baggage, acted with piercing conviction by an alert, diverse ensemble, it’s an unsensational but chilling glimpse of middle-American prejudice that, more chillingly still, hasn’t evolved all that much in the last quarter-century. Hopefully the two films will complement each other as snapshots, set 10 years apart, of a rigid Bible Belt that’s proving too slow to unbuckle. But The Miseducation of Cameron Post is noteworthy, too, as a still-rare portrayal of young female homosexuality in formative action. As the eponymous Cameron, a tender, unassertive child certain of little in life but the strength of her first sexual desire, Chloë Grace Moretz (in handily the best performance of her young career) deserves to be as much a touchstone figure for gawky girl of her generation – gay, straight or somewhere in between – as Winona Ryder in Heathers or Ellen Page in Juno.

Such figures are more unusual than they should be in LGBT cinema, even amid its current, flourishing boom. The last few years have yielded a bounty of male-oriented gay coming-of-age stories, many seemingly bound for classic status: from Call Me By Your Name to Moonlight, God’s Own Country to Beach Rats, Love, Simon to Alex Strangelove. Yet in the five years since Abdellatif Kechiche won the Palme d’Or at Cannes for Blue is the Warmest Colour – a sensuous, intimate epic charting the rise and fall of a teenager’s first lesbian romance, and sparking debate over the invasiveness of its maker’s male gaze – girls’ stories remain disproportionately underrepresented within this minority cinema. The few lesbian-themed films to have captured the wider arthouse imagination in that time – Todd Haynes’s Carol and Sebastian Lelio’s Disobedience among them – have been tales of wholly adult experience and appeal, driven by established actors rather than youth icons in the making.

John Gallagher Jr and Chloe Grace Moretz: unflinchingly calm, good-humoured and easily empathetic. Photograph: Jeong Park

Thinner still on the ground have been queer girls’ stories directed by queer women. Akhavan, who identifies as bisexual, may have just pulled off the most prominent coup in that neglected bracket since Dee Rees, whose rich, tough 2011 debut Pariah – a semi-autobiographical tale of a 17-year-old African American tomboy coming to terms with her homosexuality – was largely sidelined by audiences and awards voters alike, though it raised many of same sensitive social conflicts for which Barry Jenkins’ Moonlight was roundly and justly lauded a few years later.

Why the imbalance? It’s not as if teenage boys are falling in love with each other at any faster a rate than their female counterparts. Some may argue that male homosexuality is more received with more hostility in patriarchal society than lesbianism – making it a saltier taboo for screen treatment – yet the traumatic psychological horrors visited upon Cameron and her peers in Akhavan’s film are a stark reminder that no gay child enjoys an easy, dramatically smooth path to self-realisation. Rather, it seems that the overwhelming gender biases of the film industry at large have been unwittingly inherited by LGBT cinema, even as it fights, with growing success, to overturn other shortfalls in representation. The Miseducation of Cameron Post is so unflinchingly calm, good-humoured and easily empathetic in its portrayal of neglected queer identity that it takes a while to notice just how defiant and resistant it is to even the queer status queer: however it fares in this year’s unlikely face-off of the gay conversion dramas, its own flag is firmly planted.