The teen movie is an often raucous affair: embryonic sexual stirrings, combative parent/child relationships and the heart-tugging turbulence of post-adolescent friendship – which is why it is surprising to find Greta Gerwig’s directorial debut, Lady Bird, such a quiet and understated film. But there is perhaps something about Gerwig’s delicacy of touch that lends clarity to one of the film’s most resounding themes: its unapologetic feminism.

The central character (Saoirse Ronan) – unsatisfied with her comparatively drab given name, Christine – precociously assumes the alias Lady Bird. She dresses in thrift-shop clothes, has clumsily dyed pink hair and dreams of leaving what she deems the cultural wasteland of Sacramento, California, and her claustrophobic Catholic high-school – to study at a pricey liberal arts college on the US east coast.

Facebook Twitter Pinterest Love interest … Lucas Hedges and Saoirse Ronan. Photograph: Allstar/A24

Lady Bird is in many ways a feminist recalibration of the sort of genre tropes associated with the teen film. It seemingly has more in common with John Hughes’s hormonal outings in the 1980s than the 90s second wave (Clueless, 10 Things I Hate About You), or even more contemporary takes on the genre (Easy A, The To Do List). Lady Bird has something of the everydayness of Molly Ringwald’s various incarnations – minus the ramped-up passivity and recursive romantic trajectories that freighted many of Hughes’s films. Lady Bird has two love interests: Danny (Lucas Hedges), a sweet fellow-member of her school’s drama programme and Kyle (Timothée Chalamet), a disaffected musician of Jordan Catalano proportions. She breaks up with the former after discovering him making out with a boy in a toilet cubicle, and tires of the latter on seeing through his calculated pseudo-rebel persona.

Lady Bird's virginity is not symbolic of failure to engage with life … she does not structure her identity around sex

Lady Bird regards neither romantic breakdown as a treatise on her general worth: how she values herself is almost entirely self-determined, a bullish sense of her potential. She comforts Danny on his struggle to come out, pressing his head to her chest and tenderly raking through his hair – an instinct to nurture men perhaps inherited from her mother, who tiptoes around her father as he struggles with depression. On learning Kyle is not a virgin (though he insinuated he was), after first having sex with him (or anyone), she exclaims: “I was on top! Who the fuck is on top their first time!” Virginity is often a preoccupation in Hughes’s films, and notably for Ringwald’s characters – but unlike in The Breakfast Club or Sixteen Candles, Lady Bird’s virginity is not symbolic of her failure to engage with life, nor her apparent innocence; like her short-lived relationships with men, sex is not something she structures her identity around, rather a thing that happens.

Facebook Twitter Pinterest Romantic apex … Beanie Feldstein, left, as Lady Bird’s best friend Julie. Photograph: Allstar/A24

Lady Bird’s more romantic subplot comes from her relationship with her best friend Julie: Julie and Lady Bird drift apart following Lady Bird’s dalliance with a more popular girl, a relationship that is severed when she makes a cruel comment at the expense of Julie’s mother. Teen films often reinforce the notion women can only find fulfilment via a conventional heterosexual coupling, usually advanced by the man. Lady Bird subverts that, and the film’s romantic apex is found in Lady Bird and Julie’s reconciliation. Lady Bird ditches Kyle and the cool girl en-route to the prom to return to Julie: they slow-dance under pastel-coloured streamers then walk home holding their shoes.

But Lady Bird’s most significant relationship is surely with her mother Marion: the roundly wonderful Laurie Metcalf. Maternal love is depicted with a necessary brutality: Marion perpetually chastises Lady Bird, telling her she’s unlikely to get into the east-coast college of her dreams on account of her poor work ethic and bad grades. (Lady Bird throws herself out of a moving car in response.) It is understood she is fostering in her daughter the grit and resolve required to exist in the world, a strength she vividly inhabits. And Lady Bird, with her steely sense of a right to exist and an entitlement to pursue her ambitions, seems not to have fallen too far from the tree. Lady Bird makes it to college in New York: at a party a co-ed asks her name, and after a pause, she answers: “Christine.”