Your gut microbes might be to blame, say scientists. If you thought you were pretty well versed in the language of attraction (looks, personality, intelligence and, for some, ahem, bank balance), this news will come as a shock to you. According to scientists, who we are (and aren't) attracted to is strongly controlled by the 100 trillion microbes that live in our gut, giving pun enthusiasts even more reason to use the term 'gut feeling'.  

How so? According to the experts, these gut microbes affect our immune system response to someone else's microbes. And according to scientists, this explains why one person can smell completely intoxicating and another can physically repulse you to the point of gagging. And this becomes even more obvious when you kiss someone - the exchange of bacteria alone can make you feel ill if you've kissed a person whose microbes are out of sync with yours. Crazy stuff.

Gut feeling: the crazy role microbes play in your love life

"If the bacteria are recognised and liked, then the response is one of happiness, joy and even addiction," microbiologist Jason Tetro explained to Shape. "But if they are not aligned, then like an allergic response, the person will feel uneasy and even defensive. When that happens, it's best to move on." Point taken. And maybe it's worth popping a probiotic, too?

Interestingly, our microbes can change over time and be influenced by others. In fact, they've even done studies on couples' kissing habits, finding that couples who kiss often share more similar mouth and tongue bacterial make-up. This proves that shared lifestyle, hygiene and environmental habits (ok, and kissing) can alter our microbes. In addition to well-known research about pheromones and the way smell affects attraction, this news about bacteria proves that despite our best efforts with Tinder, Bumble, RSVP et al, sometimes attraction really does boil down to our basest animal instincts...

Gut feeling: the crazy role microbes play in your love life