Since that's clearly the way this series was put together, we might as well go through the standard archetypes of teen behavior:
The Naive, Supposedly-Good Girl Who Gets Pregnant the First Time She Has Sex. How naive? She doesn't know it might be wise to see a doctor. How good? She plays the French horn in the high school band. Amy, the putative heroine of this series, is played with wide and shell-shocked eyes by Shailene Woodley, whose main emotion appears to be confusion. She never smiles. If you're a pregnant teen, you're not allowed to smile. Especially not at the baby's father, who happens to be . . .
The Guy Who Loves a Conquest. He acts like a sleaze, but turns out to be sad, in his own way: a foster kid who wishes he were loved more by his dad. We get this information quickly and conveniently in a scene with a therapist, whose advice he does not take, because he's busy trying to conquer . . .
The Christian Girl Determined to Wait. She's blond. She's desired. Her name is Grace. She offers her boyfriend heartfelt lectures about why Jesus wants them to hold off sex until marriage - and hold off marriage until she finishes medical school. Said boyfriend tries to understand, because he's . . .
The Christian Guy Who Wants to Be Good, But Is Tempted. Because it's hard to wait until the end of your girlfriend's residency when you're being stalked by . . .
The Promiscuous Girl. In this case, she's also a smoldering Latina, who wears tight-fitting outfits and preaches the virtues of hedonism. At some point, she'll probably intersect with . . .
The Nerdy and Virginal Wisecracking Boy Who Thinks He's Falling in Love. With The Naive, Supposedly-Good Girl Who Gets Pregnant the First Time She Has Sex.