Transcript for Pheromone Parties
Some of you have been lucky to experience love at first sigh but what about love at first sniff? Here's nick watt with an explanation and it better be good. Open your minds, open your bags, take a whiff and see what happens. It's not so much about o my god, I'm smelling dirty laundry! Reporter: I beg to differ, it is exactly about smelling dirty laundry. And inhaling a stranger's pheromones, chemicals we all give off. We know some animals and insects use pheromones to attract mates. Do humans? Well, there is a bizarre craze now sweeping this great nation, pheromone parties. Seems pheromone parties are now all the rage. You get to sniff your potential suitor's pajamas. People go to this parties and actually sniff for a love connection. I'm giving a wag of my finger to pheromone parties for encouraging premarital smelling. Reporter: We attended the first-ever pheromone party in houston, texas -- where even i submitted a t-shirt, to get my nose in this smelly trend. It's kind of like rotten milk, is that yours? Yes. Reporter: This pheromone fest is attracting some key players from the city's singles scene. Confident women drive me nuts. I'm just trying to put myself in a target rich environment. Doesn't make sense at all. Reporter: And then along came holly. Nice to meet you, I'm holly, holly. All of my friends are married. I'm the go-to baby sitter. It's terrible. Reporter: And why is that? Are you too picky? Do you work too hard? I do work a lot and I travel a lot for work so I'm in and out of town every other week. Reporter: Now, holly followed the pre-party instructions to the letter. It was a three day ritual of sorts. Rule number one, buy a new white cotton t-shirt. I found some -- they smell okay, they don't have our pheromones in it yet. Reporter: Number two, sleep in it for three nights. Good night. Reporter: Number three, watch your diet. For those three days holly avoided spices, onions and garlic. I don't think, I can eat this, because there are onion in between every piece of meat -- am I compromising my pheromones? Reporter: Number four, no deodorant or perfumes. I've showered. No lotions no creams. So here's hoping I smell good. Reporter: She's imprinting her t-shirt with the essence of holly. Not sure the dog is a good idea. Until they get to rule number five, keep the t-shirt in the freezer dug the sealed in the plastic bag to preserve that natural whiff. I'm off to the party, we'll see how it goes. Reporter: Anyway, on the big night, your anonymous t-shirt is thrown into the ring. Just a number in there, blue for boys, pink for girls, everyone sniffs and picks which scents they like. Grab the photographer he'll take your picture holding that bag. Reporter: Holly chose 30. And posed with that bag for a picture. What did number 30 smell like? Clean. He smelled clean. Reporter: That's a good start in anyone's book. Okay, so from here, it works like this -- the anonymous 30 knows holly likes his smell because he'll see her holding up his number. If he likes the look of her, then he will approach. He did, but he didn't quite live up to the smell that attracted holly, so she moves on. So she goes with another, with a good old face to face attraction. I think there's a little, uh -- yeah, morgan is a cool guy. Reporter: We'll check back in with that love thang a little later. Now, organizer jennifer huthmacher claims there really might be some science behind all this animalistic sniffing. Really? Really. Reporter: Really? Really. Reporter: Evidence of love at first smell is mixed, yet a real scientific experiment found that women do prefer the scent of men with different immune systems to their own. Translation? It could lead to healthier babies. We needed to find someone who really believes this. And here she is, zoe eisenberg. A self-confessed pheromone junkie -- addicted to the smell of boyfriend phil's sweaty pits. It's little awkward with company. I really like the way he smells and we don't see each other every day so I miss him and that's kind of comforting. Reporter: Phil lives in new york city, zoe lives in connecticut, so, get this, when he visits -- this is mine, it's very ripe, it's a ripe t-shirt. Reporter: -- She keeps his dirty t-shirt and trades it for one that has lost phil's scent. A so-called handoff. It's a good one. I wear it around, some of are pretty strong smelling. Now. I'm wearing it, probably wear it for four or five days until it just smells like me. Reporter: It seems quite an intense addiction. Sometimes I do it without thinking about it, I mean he's not lifting his armpit, I'm just kind of, smelling him. Reporter: We just had to put her to the test. Hopefully it'll smell like me and she'll pick it out like a bloodhound. Reporter: It's sniff-off day. With boyfriend phil lurking behind a screen, could she possibly recognize his t-shirt, by scent alone? Can you see my hand? No. Reporter: Can you see my hand. Reporter: First t-shirt. You have to make sure the armpit is up in my face. That's not him. It's a flowery man shirt. Reporter: Eamon. A "20/20" producer. Yet another producer. Interesting decay on that one. There's your pit. That smells like him. Yup. Reporter: And here he is, the armpit adonis. Good job. I'm impressed. Reporter: I mean, it's animal and I understand it's probably biologically it's great and everything but you know we live in the modern world and this is just weird. Weird is good. Reporter: Anyway, back at that pheromone shindig in houston, my t-shirt had been chosen. That's me -- 36 hi, I'm number 36. Hello. Reporter: How are you? Hello, you smell rather nice. Reporter: Sweet lady. I liked her. But I never got close enough to sniff her -- my wife is very happy about that. Anyway, remember morgan and holly? They got a little something going. And let us tag along a few days later. And morgan brought his a game. There's the clenched fist in the arm around play. Respectful, yet amorous. But you know what? All this -- it didn't work out in the end. Interesting. Let's cast our minds back to that party where they met -- they poo-pooed the pheromone route and were attracted by each others' smiles and casual conversation, but holly did sniff morgan's t-shirt that night. It's okay, it's not my favorite smell. It smells like yogurt. Reporter: Maybe she should have trusted the pheromones and her instinct. Maybe there is something to this. Maybe we are just more animal
This transcript has been automatically generated and may not be 100% accurate.