Forget the old saying that "a way to a man's heart is through his stomach." These days, the path goes through his nose.

The latest wrinkle in matchmaking is the pheromone party, in which singles sniff dirty T-shirts in search of a scent that will lead to true love.

The gatherings were concocted by Judith Prays, a Web developer who admits that she was just looking for a novel party theme. For the first one in New York, friends were told to sleep in a T-shirt for three nights and then bring it to the party in a plastic bag. Once there, members of the opposite sex sniffed them and picked out the one they liked the best, at which point the shirt's owner was revealed.

As offbeat as Prays' idea was, she had stumbled on a scientific principle: Odors attract. Even scentless odors. "We can't detect pheromones," said Shannon Chavez, a clinical psychologist who attended a party as part of her pheromones study at SHE: Sexual Health Experts in Phoenix.

"We tend to think that attraction is based on how a person looks or acts, but now we know that the body also responds to chemical cues," Chavez said.

Chavez believes we're just scratching the surface. "The original research focused on sexual attraction," she said. "But recent research has found that pheromones also affect social behavior. They play a major role in attachment."

The next time you're throwing a party and you want to make sure everyone is compatible, just tell them to get out their dirty T-shirts and start sniffing. But you'd better be ready to explain why, or you might never see any of them again.