In the economy of heterosexual online dating, where thumbs wield the ultimate power over a person's love life, height appears to be an immensely valuable currency.

The listing of height in dating app profiles has become so prevalent, that many swipers come to expect it, and sometimes hypothesise when it's been omitted from the profile.

In my own experience, I have grown to attach a great deal of importance to the feet and inches in a person's bio. As I idly swipe through Bumble, I will scroll through a dater's photos before perusing their bio, searching for a number that might dictate the crucial decision: to swipe left or right? I'm 5ft8, and I often swipe left (which means no) on men under 6ft.

I'm far from alone in this swiping behaviour. Amber Fahrner, 6ft, says height is at the top of her list when it comes to swiping. "I enjoy wearing boots with a heel and heels itself so I would be lying to myself if I said I was OK with someone being shorter than me," says Fahrner.

She lists her height in her dating bio, and has been told by some men that she's too tall for them. "I actually don't mind," says Fahrner. "I'd rather them let me know, as it saves us both time."

Jordan Maahs, 6ft, says she had "some trouble with the height thing" when she was using dating apps. "I really only swiped right if the guy looked taller than me," says Maahs. "If his height wasn't written in his bio, I'd still eyeball it based on his pictures and generally only swiped right on guys that looked taller than me."

Emma Lumley, 5ft7, says she only swipes right on men over 6ft1. "I tend to look at the group photos and see if they’re the 'small' friend," says Lumley. "My only justification for being this shallow is that I’m 5’7” and like to wear heels!"

Stephen—who prefers to use only his first name—says his online dating experience was marred by negative interactions about his height. Stephen, 5ft10, says women would ask him his height straight after matching, and when he told them, they would immediately unmatch. He said this made him feel "ruled out, disbarred and dismissed" over an attribute he had no influence over.

"I once asked: 'wouldn't it be equally inappropriate and arbitrary for me to ask you your cup size?' to which the response was: 'no, that's absolutely not the same thing,'" says Stephen.

Kunal, 5ft11, says he's had "weird experiences" with online dating because of his height. He says that he's neither short nor "very tall." He had a "really great date" with a woman and went to arrange a second date, but she felt he was "too tall for her" as she was 5ft5. "Another time I found out that I wasn't someone's type because I was too short," he says.

He says that hearing that he's not the right height for women—particularly when he feels they've hit it off—makes him feel "slightly confused."

"Especially given that it is over something I have no control over, since I can't alter my height," says Kunal.

So, why am I—and countless others—so attracted to height in prospective matches? Are we too picky? Or, just hopelessly shallow?

Salonee Gadgil, co-host of dating podcast The Swipe Hype, doesn't necessarily think it's a bad thing to swipe left on someone because of a physical attribute. "I don’t particularly like long hair, and don’t find men with long hair attractive, so I would swipe left. Does that mean I am discriminating? Not really," says Gadgil.

But, author and "dating coach" James Preece says dating apps encourage us to be "incredibly picky" and to rule out individuals based on arbitrary qualities. "Tall men know that their height is a big selling point, so they'll mention it to attract women," says Preece.

"Shorter men will either avoid listing it at all if the app or site allows it." Some even add on a "few bonus inches," says Preece; something he says will only lead to disappointment. He believes that by swiping left on people under a certain height means daters are ruling out "amazing matches" based on "things that don't really matter."

Is it really as simple as just being "picky," though? Scientists beg to differ. Benjamin G. Voyer—a psychology and behavioural science professor at London School of Economics — says the allure of height boils down to evolution. "Height is a sign of health, and we are looking for health characteristics when we look for potential romantic partners," says Voyer.

Research by the University of Edinburgh found that our genes play a considerable role in our height preferences of a mate. By analysing the genetic information of over 13,000 heterosexual couples, scientists found that 89 percent of the genes which determine someone's height also influence their height preference in a mate.

When we spend so much time swiping through an endless stream of unfamiliar faces, it's easy to get into swiping patterns and even hard and fast rules.

Verity Hogan, eHarmony's relationship and dating expert, says that it's normal to compile wish lists that focus on "aesthetics and surface attributes" but, focusing too much on these qualities when swiping could be to the detriment of our love lives.

"By focusing on height, weight, or other physical characteristics and disregarding potential partners based on these alone, you could be missing out on the love of your life," says Hogan.

Putting genetics and evolution aside for a second, there's certainly something to be said for looking beyond numbers. Perhaps we could all do with budging an inch or two on this point.