Here are some of the most interesting facts about redheads according to La Rosa's findings:
They create their own vitamin D
Redheads have adapted the ability to created their own vitamin D due to cloudy European environments. So when a redhead goes outside, they produce more vitamin D in a shorter time period than people with other hair colours.
This gives them an evolutionary advantage too, as higher levels of Vitamin D can help prevent rickets, diabetes, and arthritis.
They have a higher pain threshold
Several studies have shown that redheaded women can tolerate up to 25 per cent more pain that women with other hair colours.
The University of Oslo also found that copper-haired females feel less pain when pricked by a pin and that they were harder to sedate.
They feel temperature more severely
The University of Louisville discovered that the redhead gene, also known as MC1R, can make redheads more sensitive to temperatures.
So if a redhead starts to feel hot or cold, it may be a sign a change in the weather is on the way.
Not all redheads are fair skinned
Native residents of Papua New Guinea, Morocco, and even Hawaii are known for their red hair and darker skin.
In Hawaii they use the term "ehu", meaning a descendant of a fire god.
They are more commercially popular
In a 2014 report by Upstream Analysis, it was found that 30 per cent of TV commercials in the US feature a redhead in a leading role.
Research also showed that the CBS network had a person with red hair appear on screen every 106 seconds.
They're perceived as having a better sense of humour
According to Professor Andrew Stott, from the University of Buffalo, circus clowns first wore bright red wigs in order to be seen from the back of large theatres.
The red-haired clown then became solidified in American culture thanks to the likes of the famous Ronald McDonald, and American's began to assume that red hair was symbolic of humour.