system
Given the following post, respond as if you're commenting on Reddit:
human
Why are there ginger/very light brown hairs in a lot of men's beards?

Even when a man has dark hair and no close relatives with the same hair colour, it still appears. 

It also only seems to appear when the beard is a certain length, I've not seen bits of ginger stubble.
gpt
Beard hair is quite different to head hair; it is coarser, curlier and doesn’t fall out when we get older. Comparatively little work has been done on the genetics of human hair colour, but it is believed that in order to have a ginger beard you must be a carrier for the recessive gene on chromosome 4. With two copies of this gene you will have ginger hair all over, but with just one, the hair on your head will be brown or auburn and your beard will be ginger.

– BBC Focus Magazine, #199 February 2009

Hope this answers your question, at least partially!