According to a twin study, women are more likely than men to have red hair even when the genotype is the same [12]. Prenatal estrogen may also affect eye color, since face shape is more feminized in blue-eyed men than in brown-eyed men of the same ethnic background [13,14].
Because red hair color generally seems to occur more frequently in women than in men (Shekar et al., 2008; Frost et al., 2017; Flegr and Sýkorová, 2019), Frost et al.
It is most common in individuals homozygous for a recessive allele on chromosome 16 that produces an altered version of the MC1R protein.
Blondes had an average IQ of 103.2, compared to 102.7 for those with brown hair, 101.2 for those with red hair and 100.5 for those with black hair. But although the new study has found blondes' IQs were slightly higher than others, the results were so close researchers have called it a draw.
Since red hair is a recessive trait, the children of two redheaded parents will almost always be redheaded as well. In contrast, if only one parent is redheaded and the other has brown hair, there is a higher chance that the children will display the dominant trait and will have brown hair.
Rarest kind of redhead
Having red hair and blue eyes is the rarest hair/eye color combination possible. The odds of a person having both of those recessive traits is around 0.17%. Instead, most redheads have brown, hazel or green eyes, according to Medical Daily.
According to an article by evolutionary biology professor Mark Elgar, PhD, of the University of Melbourne, blue-eyed redheads are the absolute rarest, with 0.17% of the population having that combination of hair and eye color.
Less than 2 percent of the world's population has red hair, making it the rarest hair color in the world. It's the result of the mutated MC1R gene. If both parents carry that gene, their child has a 25% chance of getting lovely, red locks, even if the parents don't have red hair themselves.
Research indicates that redheads have higher thresholds for pain and need less vitamin D than the rest of us thanks to the MC1R gene mutation, which gives their hair its hue.
Lifespan: up to 20 years in captivity, 5-10 years in the wild.
A study headed by Dr. Edwin Liem at the University of Louisville in Kentucky found that redheads are more sensitive to hot and cold, and are hurt by the cold at temperatures nearly 11 degrees Fahrenheit warmer than others.
One of the many facts about redheads is that their hair will never turn grey. The pigment in their hair that causes it to be red will just fade over time, causing their hair to turn blonde or white, but never grey.
People with red hair are also susceptible to feel hot and cold temperatures more quickly, as well as having a higher pain threshold. Due to this increased sensitivity, it is believed people with ginger hair find it easier to reach orgasm during sex.
'It's extremely rare for people to have hair that is naturally a strawberry blonde color. Basically, strawberry blonde is mostly based on red tones, with blonde highlights dotted here and there. It takes its name from the Italian renaissance.
Deviance, temper, and violence
Other stereotypes include that red-haired persons have a propensity to violence or are short-tempered, which are not directly supported by scientific evidence, though some research suggests they produce higher levels of adrenaline which accelerates the fight-or-flight response.
Some evidence suggests redheaded adults often appear older than their actual age. For example, one study published in 2016 in Current Biology found that adults who carry two copies of the MC1R gene variant are more likely to look two years older than other people their age.
Fun facts about red hair strands
Redheads are less likely to go grey. The pigment in red hair typically fades over time from red to blonde and white, but not grey. Redheads produce more Vitamin D in a shorter amount of time than people with other hair colors.
People with red hair are more likely to be left-handed.
Recessive traits often happen in pairs so commonly people with the gene for red hair also possess the trait for left-handedness.
Research has shown that people with red hair perceive pain differently than others. They may be more sensitive to certain types of pain and can require higher doses of some pain-killing medications. However, studies suggest that their general pain tolerance may be higher.
Worldwide, only 2% of people have red hair. People with red hair are likely more sensitive to pain. This is because the gene mutation (MC1R) that causes red hair is on the same gene linked to pain receptors. It also means redheads usually need more anesthesia for dental and medical procedures.
The skin of a redhead is thinner compared to others and is derived from the ectoderm. Teeth enamel is also derived from the ectoderm and thus is thinner than usual. Since the enamel coating is thin, the inner layer of tooth-dentin is more visible and offers a yellowish appearance.
How common is strawberry blonde hair? Having natural red hair is rare (like, two percent of the population rare), so coming across someone with natural strawberry blonde hair isn't common. While you may not be a natural-born redhead, your colorist can help you achieve your ideal strawberry blonde shade at the salon.
Contrary to what many people assume, redheads did not originate in Scandinavia, Scotland or Ireland, but in central Asia. Their coloring is due to a mutation in the MC1R gene that fails to produce sun-protective, skin-darkening eumelanin and instead causes pale skin, freckles and red hair.