I've always wished I had red hair! It doesn't seem all that common though.
It really isn't - only 1-2% of humans have red hair. I'm one of them!
You are?! Lucky! Is is more common to see gingers in certain regions?
Europe; it is centered around populations in the British Isles. Redheads today are commonly associated with the Celtic nations.
In Ireland, the percentage of population with red hair is estimated to be at around 10%, making it the world's highest concentrated population of red heads. According to IrelandsDNA, 34.7% of the Irish population carry the allele for red hair, although this doesn't directly translate proportionally into births of red-haired children.
Scotland also has a high percentage with around 6% of the population
gingers, like the ones Cartman starts associating with, and "daywalkers", people like Kyle with red hair but no freckles or light skin.
In the episode, a man tells Stan and Kyle "If you really don't want to have ginger kids, marry an Asian woman. Asians don't carry the recessive gene. I know a guy who's marrying a Japanese woman very soon for just that reason." This is an intentional reference to Parker doing the same thing in real life. He once had