The Opposite of Sex

The Opposite of Sex is a 1998 Black Comedy starring Christina Ricci, Martin Donovan, Ivan Sergei and Lisa Kudrow. The main protagonist is Dede Truitt (Ricci), a troublemaking teenage girl who leaves after home after her father dies and moves in with her gay brother (Donovan). After a few weeks she seduces his boyfriend (Sergei) into bed and ends up pregnant. After that, the two of them take off to LA, emptying the brother's bank account along the way.

Tropes used in The Opposite of Sex include:

Babies Ever After: Both Dede (and Bill by extension) and Lucia end up with kids.
Babies Make Everything Better: Played with. The end of the film has Dede preparing to leave the baby with her brother, but cuts away as she insists she won't go back. It's left open either way.
Beta Couple: Lucia and Carl
Bi the Way: Matt.
Bitch Alert: In a variation, both Lucia and Dede.
Blondes Are Evil: Dede.
Bottle Fairy: Dede is a pretty dark example.
Brick Joke: Lucia tells Dede she pronounces her name "loo-sha" because of her sisters Marcia and Tricia when her parents actually named her "loo-chee-ah". Later on she gives her name to a credit card company and spells it out for them. After a pause she snaps "yes, I know how my own name is pronounced".
Deadpan Snarker: Lucia.
Defrosting Ice Queen: Downplayed with Dede. She still remains icy but she does learn a bit about the value of family. It's left open whether or not she goes back to keep her child.
The Ditz: Matt. When Dede tells him she's late, he assumes she's talking about school.
Do Wrong Right: Bill catches a student writing an insulting statement about him on the bathroom wall. He makes the kid correct the grammar, then lets him go.
Fag Hag: Lucia still hangs out with her deceased brother's boyfriend.
Flamboyant Gay: Jason. And how.
Gory Discretion Shot: When the gun is fired in the hotel room. It leaves us in doubt whether Randy or Dede gets shot.
Hollywood Homely: Lisa Kudrow as a frumpy, sexually-repressed spinster?
Karma Houdini: Jason. He gets Bill suspended from his job after cooking up a sexual abuse story and he ends up getting the guy at the end.
Playing Against Type: Both the female leads. Ricci was known for playing adolescents and Kudrow was known as a certain airhead from New York...
Invisible to Gaydar: Bill.
No Bisexuals: Lucia certainly has this attitude. When Matt tries to explain he's bisexual, she remarks, "I went to a Bar Mitzvah once, that doesn't make me Jewish."
The Twink: Jason.
Unreliable Narrator: Dede. She even lets the audience think she dies twice.
Walking Shirtless Scene: Matt.
Would Hit a Girl: Randy gets into a literal fight with Dede in the hotel.
- Especially notable since (bitchy or not), Dede is at least seven months pregnant when it happens.