When she gives herself a pregnancy test at the local drug store (there's a rather distasteful exchange with the smart-aleck pharmacist played by Rainn Wilson) and learns she's pregnant, she decides to have an abortion.

But she's so turned off by the coldness of the abortion clinic that she resolutely decides not to have an abortion, and promises the coming baby to a childless upper-class couple, Mark (Jason Bateman) and Vanessa (Jennifer Garner), who long to adopt and have advertised in a local paper.

Complications ensue as she learns that Mark and Vanessa's marriage is less than secure, and though Vanessa desperately wants a child, composer Mark — with whom Juno finds herself platonically bonding over their mutual admiration for certain rock bands and horror films — feels quite differently. Juno is horrified to learn Mark is considering divorcing Vanessa, and begs him not to do it.

At the same time, Juno realizes that her feelings for Paulie are still strong. All of this leads to a somewhat surprising wrap-up that has just the right moral tone.

Performances are tops, including J.K. Simmons and Allison Janney as the girl's supportive — if surprisingly nonjudgmental — father and stepmother. Garner's wonderment at hearing "her" baby kick for the first time, while she kneels and speaks to Juno's belly, is an especially magical moment.

Unfortunately, Diablo Cody's wry, sardonic script contains a high expletive level for its appealing but sassy heroine, but the movie's sweet, sentimental core underneath the surface edginess wins the day. Jason Reitman's direction — beautifully attuned to Cody's unique rhythms — strikes just the right piquant tone.