"Gregory's Girl" grows on you. It's a low- budget Scots yarn about high-schoolers in suburban Glasgow, a sort of "Breaking Away" with soccer. It has no aliens; no eyepoaching visuals, no synthesized sound. It's a warm and approachable respite for movie- goers who'd like to get down to earth in a summer full of out-of-this-world adventures.

The film starts off like a soft-core "Porky's," with a set of pimply peepers outside a naked nurse's window. Oink-Oink. It's pigs in kilts, till the credits have rolled. Afterwards the pigs become people caught up in the struggle to come of age. It's a common scenario, but director Bill Forsyth modernizes it in his liberated screenplay, a winner at the British Academy Awards.

The story, performed mostly by amateurs from the Glasgow Youth Theater, sees 16- year-old Gregory through a crush on Dorothy, a striking athlete who steals his heart and his position as right sweep on the school soccer squad. Gordon John Sinclair, all pale and frumpy, is suitably gangly as Gregory, the broken-out, socially inept kind of kid Janis Ian might sing about if he were a girl.

Dorothy, acted by Dee Hepburn, is an updated heroine, a self-assured jock who wouldn't be seen dead with a pompon. She's unattainable, warn his friends and his kid sister, Madeline (Forsyth's on-location find, Allison Forster). There are some sweet scenes between the two siblings. They're a little awkward, perhaps because Forster went literally from sidewalk to set, but it feels right, considering the age differences between Gregory, 16, and Madeline, 10.

Though she's younger, Madeline's the wiser. For one thing, she's already dating, so she counsels her brother, helps him style his hair and buy new clothes and builds up his ego. Finally he swallows hard and asks Dorothy for a date.

This simple plot, filmed in seven weeks, survives a soundtrack that sounds like the Tijuana Brass's greatest hits. It's enhanced by the locations -- a crammed Scots "new town," with its traffic jam of tricycles, and a fusty high school, where kids sell doughnuts in the w.c. and a child in a penguin suit wanders aimlessly through the halls.

It's an enlightening 91-minute look at the Scots and at adolescents, most particularly boys. So, thank heaven for little boys. They grow up in the most insightful ways.

GREGORY'S GIRL -- At the Outer Circle.