Occasionally Hollywood cobbles together random members of the A-list to play family members on film, even if their genes obviously come from opposite ends of the earth. If the actors are good enough or if the chemistry is there, sometimes the combo can work, such as Ethan Hawke and Philip Seymour Hoffman as brothers in Before the Devil Knows You're Dead or Colin Farrell and Ewan McGregor in Cassandra's Dream. Other times, it stretches credibility, such as Adrien Brody, Owen Wilson and Jason Schwartzman in The Darjeeling Limited. My all-time favorite oddball casting is in Sidney Lumet's Family Business (1989), with Sean Connery, Dustin Hoffman and Matthew Broderick playing grandfather, father and son. (Huh?) At the same time, there are actor combos out there who just scream to be paired up in a family capacity. Remember Julia Roberts and Kyra Sedgwick in Something to Talk About? Well, neither do I, but that pairing was perfect. Here are a few others that could work:

1. Helen Hunt & Leelee Sobieski

They're so similar it's spooky, from their hair and foreheads, right down to the tonal quality of their voices. Anybody check the hospital records for mixed-up babies? (Helen is about 20 years older.) Not too long ago, both careers hit a peak: Helen won an Oscar while Leelee was working with Stanley Kubrick and playing Joan of Arc on TV. Now they're both in decline. For some reason, whenever Helen's name comes up, I hear "I HATE Helen Hunt!" And Leelee's last movie was for Uwe Boll. Now would be the perfect time for these two to team up in a mother-daughter drama. If they cooked up something along the lines of Terms of Endearment, with a good, solid writer and/or director, it could be interesting. Or better yet, how about something really strange and kooky with Spike Jonze or Harmony Korine? (Note: apparently the two once went head-to-head on "Celebrity Death Match.")

Gallery: Actors who could play relatives

2. Steve Martin & Dennis Quaid

Something about their diamond-shaped smiles and the angular way they speak and laugh has always struck me as vaguely similar. To me, they look more alike than Dennis and his actual brother Randy Quaid. Check out Roxanne and Innerspace (both 1987) back to back and you'll see teensy little moments here and there that kind of click -- especially their smiles, and the subsequent eye-crinkle. (Steve is the big brother, nine years older than Dennis.)

3. Christian Bale & Samantha Morton
I don't mean to harp on that old "Bad British teeth" thing, but both Christian and Samantha have front teeth that seem to curve slightly upward in the center, so that their pearly whites tend to disappear under their top lips when they speak. As a result, both speak with ever-so-vague sibilant 'S'es -- Christian more so than Samantha. (It's fairly inconvenient trait for a Bruce Wayne trying to maintain his secret identity.) But aside from that, they both have dark, intense eyes and they certainly both project a similar, singularly dedicated mood onscreen. (Christian is the big brother, three years older than Samantha.)

4. Zooey Deschanel & Chloe Sevigny

I found this one on a "celebrities that look alike" website, and it was one of the few choices there that made sense. Even their names rhyme! Zooey has bigger and bluer eyes, but both girls have those beautiful round noses, sneaky smiles and delicately husky speaking voices that suggest a unique kind of intelligence. Both actresses have always fascinated me with the way that they seem to operate both within and outside a scene, as if skillfully aware of their effect on things. Plus I've harbored a longstanding crush on both. Just imagine sitting across from them at Thanksgiving dinner! (Chloe is the big sister, six years older than Zooey.)

5. Gretchen Mol & Charlize Theron

When these two thin, pretty blondes first started making the rounds in the mid-1990s, I had a difficult time telling them apart. (Since then, Charlize has won an Oscar, plus I've interviewed them both, and so I no longer have that problem.) They don't exactly look alike, and neither one exactly explodes from the screen the way that, say, Marilyn Monroe did, but they both have tiny, pert features and a similar build. I could easily see them shopping and laughing together and perhaps sharing a low-fat latte. (Gretchen is the big sister, three years older than Charlize.)

6. Nicole Kidman & Naomi Watts

By now everyone knows that these two Aussie hotties are BFFs; neither was actually born in Australia, but both were raised there. And it's possible, but probably unlikely, that they could actually be sisters since Nicole is only 15 months older than Naomi. Again, they don't look much alike aside from the obvious blonde hair (though Nicole's is actually strawberry blonde). Nicole's eyes are much more striking while Naomi's nose is more elegant, and Naomi has those cute smile lines. But like Kelsey Grammer and David Hyde Pierce on the old "Frasier" TV show, they sort of have the spirit of siblings.

7. Meryl Streep & Natascha McElhone

One word: cheekbones. Meryl is 22 years older, so a mother-daughter movie would be most likely. Natascha isn't exactly in Meryl's league, acting-wise, but who is? Besides Natascha has done Shakespeare (Love's Labour's Lost), comedy (The Truman Show) and various types of drama (Ronin, Mrs. Dalloway), so I would think she's ready to try.

Runners up: the "Dermots," Dylan McDermot and Dermot Mulroney. This has been a running joke in my house since the mid-90s, a term used to describe good-looking, but interchangeable and unmemorable leading men. To this day, I still can't tell the two Dermots apart. Also, there's Alan Cumming and Paul Reubens, but that one's just too darn easy.