What is the reason/ cause for developing grey hair at a young age?

I'm not getting it by the way, I just don't why some young girls seem to have strands of gray in their hairWhat is the reason/ cause for developing grey hair at a young age?
i think thats stress, the stress must cause something to change the pigments in hair. i couldnt tell you exactly how though, i've no idea. o-O but one of my friends is ginger and every now and again he'll have a patch of white on his hair lol.What is the reason/ cause for developing grey hair at a young age?
it can be because of a lot of things really. mainly to do with stress and also if you use a lot of hair products and straighten/curl your hair often
HI





It can be stress - the odd hair can come through.





Or it can just be genes.





I know a girl who went completely grey at 18... and so did her mum.





X
genes i guess. im 16 i have so many.but hey what can i do......