Khloe and Kim Kardashian tart it up at a Halloween party last year. Photo: Mark Sullivan/Wireimage.com

Two of my sisters live in L.A. One is about to be 40. The other is just about turning 30. Neither are married with kids and both are insisting on going out for Halloween.

Guess who's going as the sexy kitten and who is going as the "night sky" (which I correctly predicted would involve a black Virgin Atlantic sleep suit with cotton balls attached)?

Oh Halloween, that time of year when parties are packed with women in sexy nurse outfits offering to take your temperature and the men who ply them with drinks, hoping there's a chance in hell that this will actually happen.

I'm not sure when a holiday rooted in the tradition of summoning spirits turned into a reason to get your boobs out. (Perhaps we could thank that early '80s seductress Elvira for kicking off the trend.) I actually stopped celebrating this less-than-sacred occasion years ago. (Full disclosure: My birthday is the night before and it is an actual physical impossibility to partake in more than one evening of festivities, since my liver went on strike after I turned 25.)

I also blame my paranoid Jewish mother, who has a history of looking at Halloweeners and shrieking, "Look at them! A room full of drunk men with masks on their faces and women with nothing on! Anything could happen and who would know? How would you identify anyone? It's like a pervert's dream!"

And, crazy as she can be, I hate to admit: She's not entirely wrong. Paranoid, but not wrong.

Most people treat Halloween like a free pass (especially if it happens, as it is this year, on a weekend). Go to any bar across the country and you're surrounded with women who are proudly displaying their wares. No matter how old they are.

When I posed the question on Facebook as to why women decide to slut it up on this particular night, the commentary was quite colorful. It ranged from predictable ("It's the one night you can dress like a slut without actually being one, LOL") to psychological ("It's about the shadow aspects of one's persona and the permission to become that, even for one night"), with a smattering of the disturbingly Freudian thrown in for good measure ("Could it be that women are all sluts underneath?! Freud would say yes and personally, I love the fang and snarl of S-E-X").

An older friend attributed Halloween to more of a primordial dance of sorts, like a National Geographic segment. "Basically, a woman wants to look and act slutty to attract a man! Why else?" she wrote authoritatively.

Could costume designers be to blame? I mean, where are the wholesome ensembles? When do little girls graduate from fairy princesses to pop tarts that attract pervs like heat-seeking missiles?

"It's really hard to find a costume that isn't slutty to begin with," lamented one gal pal. "You will need to create one yourself... and frankly, most people have little time or interest in creativity anymore."

All of which is hilarious -- especially in New York, where the weather has taken on a crisp fall chill. Ladies yearning to be free from their daily id -- and possibly get some nookie (which may just improbably lead to marriage and children) -- must then keep up the sexy act while shivering and trying not to stammer through their gritted frozen teeth as they shake their Miss Kitty thang to another bar.

So yeah. I'll be at home with my dog and a packet of Noodle Roni, getting updates from the street from my sisters, one of whom will be the Night Sky. Because she's given up.

For more trick-or-treat fun, check out Heidi Klum's Halloween costume evolution.

And click here for celebrities who play dress-up pretty much on a daily basis