(NEW YORK) -- Redheads, as they say, wear the map of Ireland all over their faces. And the statistics bear that stereotype out.
Anywhere from 10 to 30 percent of all the world’s redheads live in Ireland, according to Eupedia, a website that explores European genetics and ancestry. An equal number also lives in Scotland and other pockets of Celtic pride. Slightly fewer hail from Cornwall in England and western parts of Switzerland.
Red hair is associated with the gene MC1R, a recessive and somewhat rare gene that occurs in only about 2 percent of the world’s population, according to the National Institutes of Health. That means both parents must carry a copy of the gene to produce a red-haired child and often the trait skips generations.
Rarest of all are redheads with blue eyes. The majority have brown eyes or hazel or green shades.
Brian Braiker, a New York City editor who answered an ABC News call for redheads with, “Better red than dead,” said he is “always” mistaken for an Irishman. Ethnically, he is nearly all Sephardic Jew, except for a maternal grandmother who is Norwegian.
Genetic genealogy has revealed a high percentage of people from southwest Norway coincide with a paternal lineage known as haplogroup Rib-L21, including its subclade, Rib-M222, which is typical of northern Ireland. Genealogists speculate that may be because the Vikings took Celtic slaves from Ireland to that part of Norway.
Braiker, 6-foot, 3-inches tall, with his brown eyes and full-fledged auburn beard, said he didn’t have an easy time of it growing up a redhead. His coloring was nothing like his dark-haired father and mother.
“I endured jokes, ‘Are you the milkman’s son?’ and ‘Were you adopted,’” Braiker, 39, told ABC News.
The gene apparently skipped a generation or two, as he confides his father’s uncle and a maternal cousin also had red hair.
One ancestry company, BritainsDNA, now offers parents the chance to see if they carry the recessive gene by sending in their saliva for testing. If both do, they have a one in four chance of conceiving a redhead. BritainsDNA conducted the biggest study of redhead genetics in the country, with more than 2,300 people who have undergone DNA tests.
Redheads like Braiker are more sensitive to hot and cold. And one 2008 study published in the New England Journal of Medicine revealed they need about 20 percent more anesthesia to knock them out for surgery.
Redheads are also better at making their own vitamin D, which helps protect against osteoporosis, because their bodies are more efficient at soaking up sunlight, according to Yahoo Health. Scottish researcher Jonathan Rees suggests the “ginger gene” may have helped protect redheads from rickets.
According to an article in Huffington Post UK, redheads share some other interesting traits: their hair is harder to dye than other shades; they have fewer, but thicker strands of hair; and they go grey more slowly.
But there are also health disadvantages.
The color of human skin, hair and eyes is dictated by two types of melanin pigment that are produced in the upper layers of the skin: pheomelanin, which is reddish-yellow, and eumelanin, which is brownish-black.
A 2012 study from the journal Nature, found that the pigment pheomelanin, which gives hair the red color, makes redheads more susceptible to melanoma than fair-skinned blonds, even when they cover up their skin.
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