Today is the day you've all been waiting for: National Kiss a Ginger Day.
So what better way to celebrate than to learn the science behind one of life’s eternal mysteries?
Unless you can track down Ed Sheeran, that is.
No doubt you've wondered at some point in your life, why certain men have ginger beards... But not red hair on their heads.
Only a very small percentage of people are true readheads, but they’re not the only ones who can grow ginger beards.
It's all thanks to a genetic mutation of the MC1R gene.
This gene plays a vital role in the production of melanin, the amount of which determines hair colour, according to genetic scientist Petra Haak-Bloem.
MC1R makes a protein called melanocortin 1, which converts pheolmelanine (red pigment) into eumelanine (black pigment).
Haak-Bloem told Motherboard that we each inherit two MC1R genes, one from each parent.
When someone inherits two mutated genes, they have red hair. And if only one gene is mutated, this is when you end up with a ginger beard and mismatched hair.