A swanky topless club has found an astonishing way to keep its doors open despite Mayor Rudolph Giuliani's clampdown on X-rated cabarets and smut shops: Let children in.

"This is, like, nuts," the mayor moaned. "These are sick, perverted places. What do you want kids in there for?"The U.S. Supreme Court gave the city the green light in July to clean up its red-light districts with a tough law that banished strip clubs and sex shops from most neighborhoods.

But a sharp lawyer for Ten's World Class Cabaret in Manhattan figured out that since the law specifically targets "adult" establishments, putting out the welcome mat for children would save the club from a padlock.

Trial-level state Supreme Court Justice Stephen Crane agreed Thursday, saying Ten's "cannot be defined as an adult eating and drinking establishment if it does not exclude minors."

"There's nude Shakespeare. There's movies with nudity. Why pick on Ten's?" asked the club's lawyer, Mark J. Alonso.

"You could take your 15-year-old son to see the movie `Striptease.' Why can't you take him to see a striptease?" Alonso asked.

Giuliani called the decision "one of the jerkiest rulings I've seen" and accused the judge of ignoring the intent of the law, which prohibits sex-oriented theaters, bookstores and dance clubs from operating within 500 feet of homes, day-care centers, houses of worship, schools or one another.

The city will appeal.

The adults-only language was included in the law so as not to interfere with what city lawyers called "legitimate theatrical performances and films including nudity or having a sexual theme."