Redheads are a rare group, comprising only around 2% of the global population, yet they have inspired a rich tapestry of folklore. From being considered temperamental and devil-associated to being linked with witchcraft and vampire lore upon death, redheads have been surrounded by intriguing myths. “Red is such an extraordinarily important color for the human species, and it does get associated with passion and fire,” says Jacky Colliss Harvey, author of Red: A History of the Redhead.
Red hair is a recessive trait passed down through genes, requiring both parents to possess the gene variant to pass it on to their children. Interestingly, the parents don’t need to have red hair themselves to have a ginger-haired child. They can be carriers of the recessive gene, with the instructions for red hair hidden in their DNA. This can lead to families that haven’t had a redhead for generations unexpectedly welcoming a red-haired baby.
The MC1R gene, responsible for determining hair, skin, and eye color, plays a crucial role in the rarity of redheads. Redheads typically have mutations in their MC1R gene, making them uncommon. If a redhead also has blue eyes, the rarest combination of hair and eye color, it’s considered a genetic rarity.
Evolutionary biology expert Mark Elgar, PhD, from the University of Melbourne, notes that the likelihood of possessing both traits is approximately 0.17%, equating to around 13 million individuals out of the global population. The rarity of this combination stems from the complexity of multiple genes and variations at play, coupled with the recessive nature of both traits, making it unlikely for two parents to pass down two sets of recessive genes.
Although red hair is considered one of the rarest hair colors globally, redheads continue to thrive across the vast expanse of our world. With approximately 2% of the population being redheads, there are around 158 million individuals with fiery locks roaming the planet.
Interestingly, Ireland boasts the highest concentration of redheads at 10%. Despite their rarity, the genes for red hair are not diminishing. Even if recessive traits like red hair are not visibly expressed, they remain a part of an individual’s DNA, coexisting with dominant traits like brown hair and brown eyes. This implies that the possibility of red hair appearing in future generations remains entirely feasible.
“There’s no question that red-haired individuals are at a much higher risk for skin cancer than brown-haired individuals,” according to Dr. Gregory Papadeas, a dermatologist in Denver and former president of the Colorado Dermatologic Society, this encompasses melanoma, a type of cancer that originates in melanin-producing cells and is considered one of the most severe forms of skin cancer.
In contrast to individuals with different hair colors, redheads possess two copies of the MC1R gene. This gene plays a crucial role in melanin production, influencing the color of hair, skin, and eyes. The MC1R gene instructs melanin-producing cells to produce either eumelanin, commonly found in darker hair and skin, or pheomelanin, typically associated with lighter hair and fair skin tones.
“Melanin works as a shock absorber, protecting you from ultraviolet light. It’s a person’s innate sunscreen,” says Papadeas. Redheads experience a mutation in the MC1R gene, leading melanocytes to predominantly produce the reddish pigment pheomelanin. Due to the elevated levels of pheomelanin in redheads, they are more vulnerable to sun damage.
A comprehensive review published in PLOS One in 2017 revealed that women with red hair face an elevated risk of gynecological cancers like cervical, uterine, and ovarian cancer. The study’s authors suggested that this heightened risk could be linked to higher prenatal exposure to estrogen. Prenatal estrogen not only impacts the onset of specific health conditions but also influences the development of certain hair and eye colors, particularly red hair.
“Estrogen creates a predisposition to certain types of cancer, and it looks like there’s a three-way relationship between being a woman, having red hair and having these diseases,” says Peter Frost, PhD, an anthropologist specializing in the impact of sexual selection on shaping observable human characteristics, who commented on the subject. In a study published in Current Biology in 2016, individuals with two copies of the MC1R gene, responsible for red hair, were found to appear up to two years older than those without both copies. The authors noted that this aging effect was comparable to the impact of smoking on perceived age.
Surprisingly, the association between red hair and aging was not attributed to skin damage from sun exposure, which typically causes wrinkles and dark spots. Instead, the gene variants seemed to influence pathways related to skin sagging and other factors. The authors highlighted this as the first indication of a genetic influence on perceived age. The possibility of this discovery leading to the fountain of youth remains uncertain. Multiple research studies have indicated that women with red hair exhibit an increased tolerance for pain.
“The pain threshold is the limit from where you don’t feel anything to where you just start to feel pain,” explains David Fisher, MD, PhD, the head of dermatology at Massachusetts General Hospital, who has conducted numerous research studies on individuals with red hair.
In a study from 2021 co-authored by Dr. Fisher, insights were gained into this phenomenon. The research focused on red-haired mice, which share similar MC1R variants with humans, revealing that the MC1R gene linked to red hair also plays a role in regulating the expression of factors that influence specific pain sensations. Essentially, melanocytes in redheads release substances that prioritize signals to the brain signaling “don’t feel pain” over “feel pain.” Dr. Fisher suggests that these discoveries could potentially pave the way for safer pain-relief medications compared to those available today.
A study published in the journal Anesthesiology revealed that women with red hair needed up to 20% more anesthesia to maintain sedation compared to those with dark hair. This is attributed to differences in pain sensitivity and tolerance rather than pain threshold. Sensitivity levels may vary depending on the type of pain experienced, such as heat, cold, electric shocks, and stinging pain, although specific research findings differ. This characteristic could help explain why individuals with red hair often exhibit greater fear of dental procedures and tend to visit the dentist less frequently, as reported in a study in the Journal of the American Dental Association.
The reason behind this phenomenon, much like blushing, remains unclear. However, researchers speculate that individuals in regions with limited UVB exposure, such as parts of central and northern Europe, may have developed this trait to adapt to environments with scarce sunlight. Dr. Fisher suggests that the MC1R variant, through evolution, provided an advantage in promoting healthier vitamin D synthesis.
But redheads may require more anesthesia: Research indicates that redheads may have a higher general pain tolerance, but they also experience pain differently and may require different pain management approaches. The relationship between red hair and anesthesia is still under investigation, with both scientific studies and personal accounts suggesting that redheads need more anesthesia for sedation.
There are differing opinions on whether individuals with red hair require higher doses of anesthesia, with a study in the Canadian Journal of Anesthesia suggesting that they may not. The connection between red hair and anesthesia is still being explored, but Dr. Fisher emphasizes that individuals with red hair, like everyone else, should communicate their pain levels. He stresses the importance of speaking up about pain rather than dismissing it as hysteria.
Redheads have been found to produce more vitamin D, crucial for bone health and synthesized through exposure to UVB rays from the sun. A study in Experimental Dermatology in 2020 discovered elevated levels of calcidiol, a vitamin D precursor, in redheads, indicating a potential for increased vitamin D production compared to individuals with different hair colors. The amount of calcidiol present also correlated with the intensity of red hair.
Research has delved into the perceived personality traits and attractiveness of redheads. In one study, a woman was instructed to visit various nightclubs with her hair dyed blonde, brunette, and red. Men approached her more often when her hair was blonde. Additionally, 126 men rated images of the same woman in the study published in the Scandinavian Journal of Psychology. The redhead was perceived as the least shy, the most temperamental, and the most sexually adventurous among all hair colors. Brunettes were viewed as more approachable, while blondes were seen as more dependent.
A study co-authored by Frost in PLOS One suggests that redheads may have a higher number of children, even though they face more fertility challenges. The reasons behind this phenomenon are not definitive and could be attributed to various factors. One observation is that redheads tend to begin having children at a younger age.
Studies have indicated that women with red hair may engage in more sexual activity, although experts are skeptical about whether this is influenced by their partners. A study from 2022 published in Frontiers in Psychology examined 110 women, with 34% being redheads, revealing that redheaded women scored higher in terms of sexual desire. They reported engaging in more sexual activity and having more sexual partners. Additionally, redheads were found to become sexually active at an earlier age compared to individuals with different hair colors.
