1. Birth (2004)
The pairing: Anna (30s) and Sean (10)
In Anna's defense, she's pretty sure the 10-year-old boy she makes out with is actually her dead husband. On the other hand, she makes out with a 10-year-old boy. It's never really OK.
2. Labyrinth (1986)
The pairing: Jareth (ageless/30s) and Sarah (teenager)
At some point, all of us lusted after David Bowie and his codpiece. But sex appeal aside, there's something wrong about the Goblin King cozying up to a teenage girl.
3. Lolita (1962)
The pairing: Humbert Humbert (40s) and Lolita (12)
Ah, the classic age-inappropriate romance. Lolita is the definitive fictional example of the young girl and the much older man — after all these years, it's still intensely creepy.
4. Wild Things (1998)
The pairings: Sam (late 20s) and Kelly (teenager), Sam and Suzie (teenager)
Oh, what a tangled web these three weave. While we eventually learn — spoiler alert — that Sam never raped his students, he still engaged in completely inappropriate relationships with them.
5. American Pie (1999)
The pairing: Stifler's mom (40s) and Finch (teenager)
Was Finch 18 by the time he lost his virginity to Stifler's mom? Let's hope so. Either way, a high school student being seduced by a MILF is pretty unsettling, no matter how good of a match they seem to be.
6. The Graduate (1967)
The pairing: Mrs. Robinson (early 40s) and Benjamin (21)
This pair-up isn't illegal — it's just wrong, especially since Benjamin is otherwise involved with Mrs. Robinson's daughter Elaine. Who wants her mom's sloppy seconds.
7. Poison Ivy (1992)
The pairing: Darryl (40s/50s) and Ivy (teenager)
No matter how precocious and homicidal Ivy is, there's no excuse for this icky transgression. She's just a teenager, albeit a crazy one.
8. The Reader (2008)
The pairing: Hanna (36) and Michael (15)
She's sleeping with a teenage boy and she was a Nazi prison guard. The fact that Hanna can't read seems like the least of her problems.
9. Fish Tank (2009)
The pairing: Connor (30s) and Mia (15)
It's hard to see someone as dashing as Michael Fassbender play a creep, but he's really quite good at it. His seduction of his girlfriend's teenage daughter ends terribly, as these things usually do.
10. Big (1988)
The pairing: Susan (30s) and Josh (12)
OK, here's the thing — when Susan sleeps with Josh, he's in the body of Tom Hanks. But on the inside, Josh is still a 12-year-old, and that does put a damper on the relationship.
11. Tadpole (2002)
The pairings: Diane (40s) and Oscar (15), Eve (50s) and Oscar
Oscar has not one but two older women chasing after him. He welcomes the attention and does have a predilection for more mature women. But 15 is a bit young for either of them to reciprocate his feelings.
12. Liberal Arts (2012)
The pairing: Jesse (35) and Zibby (19)
The age difference here isn't too extreme, and Zibby is of legal age. That having been said, it's always unsetting when a professor sleeps with a student at his college, even if she's the one doing the seducing.
CORRECTION: They never actually sleep together, and he's not a professor at her college. So the romance in Liberal Arts isn't really creepy at all — though some would consider the age gap to be inappropriate.
13. Manhattan (1979)
The pairing: Isaac (42) and Tracy (17)
Woody Allen's penchant for younger women aside, his character's relationship with a 17-year-old girl is weird and disconcerting. What do they see in each other, anyway?
14. The Crush (1993)
The pairing: Nick (30s) and Adrian (16)
Another mentally unbalanced teenage girl latching on to an older man. Again, Adrian needs a lot of therapy — and so does Nick after the ordeal she puts him through.
15. American Beauty (1999)
The pairing: Lester (40s) and Angela (teenager)
Lester and Angela never actually consummate their relationship, but they spend a lot of time building up to it. That Lester is crushing on one of his daughter's friends is bad enough, but Angela is also underage.
16. Harold and Maude (1971)
The pairing: Maude (79) and Harold (early 20s)
It feels a bit unfair to put Harold and Maude here. But while it doesn't hold them back, their age difference is central to the film. And it's ultimately what tears them apart: Maude kills herself when she turns 80.
17. The Mother (2003)
The pairing: May (60s) and Darren (30s)
Good on May for hooking up with a man half her age. But did she have to go for a married guy who's already cheating on his wife with May's daughter? It's complicated and a little bit gross.
18. Notes on a Scandal (2006)
The pairing: Sheba (30s) and Steven (15)
Judi Dench's Barbara is such a destructive force, you almost forget about the creepy student-teacher relationship at the heart of the film. Basically, everyone in this movie is messed up.
19. The First Wives Club (1996)
The pairing: Bill (40s) and Phoebe (16)
Bill thinks his hot young girlfriend is of legal age — alas, like so many Hollywood actors, she's lying. Who knew she'd be pretending to be older than she really is?
20. Twilight (2008)
The pairing: Edward (104) and Bella (17)
He's 104. Any questions?