Ok, so meeting 'the one' is a bit of an anachronism these days. Not many of us are still labouring under the illusion that there is only one perfect match for us in the world.

However, it is, of course, true that we are better matched with some people more than others.

So you've hooked up with someone new and it feels like the world might have stopped turning, you've got so much chemistry. Was it the sparkling eyes, the sense of humor, or the love of death metal?

Despite being a walking heart-eye emoji, it probably wasn't any of those things. One of the real secrets of white-hot attraction is something a lot less sexy, according to a recent study published in Nature: It's a part of your genetic coding.

All humans have their own unique human leukocyte antigen (HLA) complex, which helps the immune system differentiate between its own cells and those of unwanted viruses and bacteria. But they also can be hugely influential when it comes to attraction. The researchers studied attraction patterns in 254 couples and found that having a partner with a very different HLA complex "correlates with sexuality and enhances the desire to procreate." That means your genes determine how badly you want to get it on with your partner. So opposites do attract!

It also might account for why you think significant other smells sooooo good. The researchers saw that most of the couples were more inclined to think fondly of their partners' odor if their HLAs differentiated. (However, the researchers noted that because predilections for odor were self-reported, it could have been influenced by the fact they were already smitten and in a relationship.)

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Science could be why you want to throw yourself at the guy you love.

All of this is more than just quirky trivia to shout out at a bar. It can actually benefit evolution — at least, in the case of animals. The researchers found that if two animals with unalike major histocompatibility complexes (or MHC) — which is what scientists call all animals' version of HLA — loved each other very much and they mixed their bodily fluids together, then their baby would be born with a super-charged immune system.

Instead of asking "hey, baby, what's your sign?" next time you're out, try asking "what's your genetic HLA blueprint?"

From: Redbook