What's your smell

Your scent makes me so wonderfully weak

Not just without the candlelight dinners familiar to the pizza advertisement with glances and oaths turn women and men into lovers. But falling in love has to do with mouthwashing: The saliva proves whether a couple is biologically compatible.

She sat dreamily, the stranger, for example, at the table in a café, as if she had a veil in front of her eyes. She was thinking about something beautiful, so she temporarily blocked out reality. She found herself beautiful in her daydream, and when a smiling face from the next table crossed her gaze, she smiled back devotedly. Thus began a romantic affair that made two people companions. Two out of twelve million singles in Germany who are looking for great love.

But love alone is not enough, feelings are not reliable enough, says Joelle Apter, 33, a Swiss biologist. What comes up in a sober room of the GenePartner company in Aldiswil, a desolate suburb of Zurich, drives the romance out like a whip. "It is only the right person and the right person if both belong together biologically," says the co-founder of the genetic testing company. Joelle Apter and her business partner Tamara Brown, 34, a molecular geneticist, believe they have found a surefire way to bring ideal partners together - using a DNA test.

The promises are enormous. "Genetically highly compatible people have the rare feeling of perfect chemistry for one another," whistles Apter. "This is our body's receptive and welcoming response when immune systems are in harmony." Then she becomes pithy and enumerates the consequences: better sex. A higher likelihood of a fulfilling and long-lasting relationship. Healthy children. "The clarity about the biological ensures more security." Security is not boring in the long run, on the contrary, it makes "permanently happy".

The happiness of love unfolds when couples have sufficient differences in genetics. It is socially beneficial if the partners come from the same milieu. It makes a lot of things easier when you understand each other's interests and ideas about life. However, biology in its evolutionary twist wants maximum gene diversity. The MHC code is decisive. These proteins bind bacteria and viruses and boost the body's immune system. A person who has a large number of different MHC proteins can cope better with pathogens. If it mates with a person who also has a large number of different genes, this is the optimal combination from a biological point of view. It strengthens the offspring, which can adapt to their environment in a more varied way. Genetically similar contemporaries, on the other hand, produce weak offspring.

And how do the two notice that they are highly compatible? "Of course on a genetic test," says Joelle Apter. "But subconsciously they smell it too." MHC genes influence body odor; a person's individual pheromone cocktail is brought closer to the other through their sweat. During the encounter, the sniff test happens unconsciously. If heads come together while flirting, hands and upper bodies touch, the odor from the vomeronasal organ is perceived on both sides of the nasal septum. From there, the scent notes reach the brain as chemical messengers, which react with joy or defense. Even before the first kiss, a man and a woman know instinctively whether they belong together. The vernacular knows: You have to be able to "smell" the other.

In an experiment, the biologist Claus Wedekind from the University of Lausanne had three men wear the same T-shirt for three days. They moved in it during the day and slept with it, were not allowed to wash, and deodorants and perfumes were also forbidden. Then three women sniffed the T-shirts and stated which one they found attractive. The result was clear: every woman found the most attractive scent of the man whose MHC genes could be most clearly distinguished from theirs.

Far too biologistic, say critics. You also have to consider social and psychological components. "Yes," replies Joelle Apter. "But that can also be misleading." Especially psychological coaches who worked with lists made everything more difficult. And she tells of a woman who explained to her coach that she was looking for a partner who was not allowed to be a smoker. But there was one Qualmer who was particularly interested in her. The genetic test revealed that the two were a good match. Then they would have tried it. It is not known whether he quit smoking or she became a smoker. The dissuasive psycho-uncle was booted out. "It would have been a shame if Mrs Right had missed her Mr Right," said Apter.

The genetic test is carried out with a swab. Put it in your mouth, scrub the inside of your right cheek around 20 times and your left cheek as often. The brushes are then left to dry for an hour, packed in plastic bags and sent to Switzerland. From there, the spit is sent to a company in Houston, where the DNA is determined, which is then compared with others in Aldiswil. To the USA because Swiss laboratories are too expensive and extensive. "We only need a percentage and not many details, such as are necessary for bone marrow transplants," explains Joelle Apter.

The customer receives the result with a click of the mouse after paying 80 euros. A percentage below 60 is "difficult", according to the managing director of GenePartner. "Everything about it is good to very good." She herself got to know her husband "normally" when she hadn't founded the company yet. Later they did the genetic test and it was over 70 percent. With a friend, Apter even made it to 90 percent. "But I only find him attractive while my husband and I have a physical feeling of togetherness." By the way, she is expecting a child.

The process of creating an identity of one's own genetic material with a swab and comparing it with other IDs is an invention of the company Scientificmatch.com in Boston. As a customer, you can search through your genetic material there and be brought together with compatible people via a partnership portal. The US firm even promises that partners who are genetically well-matched will be more loyal than others. That goes too far for Joelle Apter. "The risk of flinging is far too high, especially at a young age," she says. Most of the more than 1200 customers in GenePartner's database are between 40 and 50 years old, women often in their mid-30s, customers under 30 in the minority. Offers are made to those who want to find a partner via the company's website. "But we do not reveal why we bring someone together with someone, that is our trade secret," said Apter. But it is not played fate, one proceeds strictly according to the biological guidelines.

The beautiful dreamy girl from the café and her companion did the test, but are not waiting for the result. They know that they belong together. The scent of their love keeps them enchanted. The genetic test could only confirm that. The feeling wins.

Interested in a love test? Visit: www.genepartner.com