I must preface: I love redheads. I think people with red hair are generally more attractive, interesting and unique than the rest of us. I have several friends on Facebook who always tag me when they find Tumblrs full of redheaded guys, and I stare wistfully at women with long red locks when I see them out and about (I try not to be obvious about it). When I was a teenager and I was really hard on myself about my looks, one of the top three things I was disappointed about was not having red hair. (My own hair is naturally mouse brown, but I have dyed it red since I was 16.) I mean, I could have been born a ginger, as I have ancestry in both England and Scotland — but only 1-2 percent of the population of the world is has the gene, and I just didn't get lucky. 

Now that we've gotten my intense adoration of redheads out in the open, let's proceed.

I recently heard that climate change may hasten the decline — and lead to the eventual elimination — of redheads from the gene pool. I was alarmed, but when I read up on it, I found that the idea is kind of conjectural, and in any case, won't happen for a good long time. Once you understand the background, it becomes more obvious why: 

Redheads are most common in Ireland and Scotland (about 13 percent of Scots have russet locks, while 40 percent of the population carries the recessive gene), and then Wales and northwestern England, and Germany, which is why it is known as a classic Celtic and Germanic trait. But what's interesting is that some population geneticists actually believe that the red-hair gene originated in Central Asia (followed by a migration of some of those people with the gene);That explains the Tarim mummies, which have been found to have the gene, and Central Asian communities like the Uyghur, where red hair is prominent. Specific groups in Morocco, especially the Riffians have red hair (about 10 percent of the population do), and there are other communities in Northern India and Pakistan where red hair pops up. And of course within Europe, redheads occur at much higher rates in the Ashkenazi Jewish community than in non-Jewish ones. This all makes sense if you think red hair originated in Western Asia and then spread west, leaving groups with the gene behind. 

Map of red hair frequency in Europe

The other theory is that red hair evolved in the British Isles due to the need there for more vitamin D due to more northern latitudes (less light) and cloudy skies. Lighter skin is better at absorbing sunlight and making vitamin D, and red hair genes travel with light skin genes. People with lighter skin would have had some advantage in making vitamin D in northern latitudes if they had lighter skin — but this doesn't really explain other groups that have historically had red hair in other areas that were less northern, or that the majority of people in Scandinavia don't have red hair.

The truth is that nobody seems to know exactly where red hair comes from, and it's a topic still debated among anthropologists and genetics experts.

What scientists do know is that red hair is caused by a specific recessive gene, discovered in 1997: MC1R on chromosome 16. About 80 percent of people with red hair have this gene (which has three variants) and it effects the balance between two types of melanin in hair. Eumelanin (more common) causes dark hair and dark skin or helps lighter skin take a tan. Pheomelanin has a pink/red color and is responsible for red hair and freckles. Among people with a predominance of eumelanin, any rufosity (redness) in their hair won't be very visible, even if it's expressed. 

So, knowing what we do and don't know — will redheads go extinct in the near future, from climate change, or something else?

"I think the reason for light skin and red hair is that we do not get enough sun and we have to get all the vitamin D we can. If the climate is changing and it is to become more cloudy or less cloudy then this will affect the gene," said Dr. Alistair Moffat, managing director of Galashiels-based ScotlandsDNA.

Since the original "redheads are going extinct" story has been proven to be untrue, losing redheads to rising temperatures is also unlikely, despite what Moffat says. With .5 percent of the world redheaded — that's 40 million people — (and many, many more carrying the gene for it), and with the redhead gene sometimes skipping several generations before it shows up again, redheads aren't going extinct. And considering that most of us don't live our lives outside anymore, even fairly extreme climate changes won't affect genes as much as it would have in the past. At least not anytime soon.   

So what IS true about redheads? 

They do have a higher skin cancer risk (and it may have little to do with sun exposure): "Even if you're good about avoiding UV rays — you know, putting on sunscreen, wearing protective clothes and being careful at the beach — it's still possible this red pigment [pheomelanin] is related to carcinogenic activity anyway," said Dr. David E. Fisher, director of the melanoma program at Massachusetts General Hospital in Charlestown and senior author of a study in a 2012 issue of Nature.

Several more recent studies have shown that redheads need more anesthetic and experience pain more intensely than non-reds. They are more resistant to local pain relievers like Novocaine. According to the New York Times, "The MC1R gene belongs to a family of receptors that include pain receptors in the brain, and as a result, a mutation in the gene appears to influence the body’s sensitivity to pain. A 2004 study showed that redheads require, on average, about 20 percent more general anesthesia than people with dark hair or blond coloring."

A Dutch festival, called RedHeadDay is held yearly in September in the city of Breda in the Netherlands. It's a gathering for natural redheads, but also a celebration of art that's red. 

The term "redhead" has been in use since at least 1510.  

Princess Lalla Salma of Morocco has curly, auburn hair. There's a 50/50 chance that Prince George of England will have red hair, and recent pictures make that seem more and more likely!

There is a long history of discrimination against gingers (sometimes seen as a derogatory term, sometimes not) in the UK: There was even a "Kick a Ginger" Facebook group.  

Looks like much of what we think about redheads is true — they are uncommon, a little mysterious, and definitely gorgeous (OK, that last one is just what I think!) 

Related on MNN: 

The opinions expressed by MNN Bloggers and those providing comments are theirs alone, and do not reflect the opinions of MNN.com. While we have reviewed their content to make sure it complies with our Terms and Conditions, MNN is not responsible for the accuracy of any of their information.