I have many more gray hairs than I am entirely comfortable with at the ripe old age of 27. There are now three reasons why this might be:
1) Emotional/mental stress
There is no scientific evidence (yet) to support this old-wives tale and favorite reason of grey-haired fathers with teenage daughters across the globe. Also, I’m not a particularly stressed-out person, especially if you compare me to the rest of the graduate student population in the US. So it seems unlikely that this is the cause of my early silver highlights.
2) Genotoxic stress
According to a recent paper in Cell (Inomata, K. et al. 12 June 2009) gray hair can be the result of genotoxic stress to your hair follicle’s melanocyte stem cells. The researchers subjected mice to IR and, voila, the mice now have inferiority complexes and can’t get any of the 6 week old mice to notice them a very distinguished look to them.

3) Genetics
My mom didn’t start going gray until her 50’s, but my Dad definitely had a little salt and pepper going on by his mid to late 30’s. Still, I’m at least a decade earlier for the onset of gray hair than the appearance of my parents would predict. And blaming “my genes” just seems cliche these days.
So while the third reason seems the most likely, I might look into the rate of early gray hair among grad students working in organic chemistry labs. I should be able to find a link with a p-value of at least 0.1 ;)
I got my first white hair at the age of 18. They’ve multiplied since, but luckily I escaped my maternal grandfather’s fate (completely grey/white by the age of 30). The worst part is that, unlike the rest of my hair, the white ones don’t curl, but rather stick straight out. So even dying it doesn’t help!
Yes, my first was around 18 but I met my relative’s fate of grey by 30. But just tell yourself, all-powerful Gandalf the White had to be Grey first. Really interesting post!
I agree, great stuff!
I suspect that it’s my red hairs that went white first. My husband and his two brothers have the same issue – all 3 of them have identical white patches in their beards/stubble that used to be red! Two little strips on either side of the chin.
I started to go gray about a year ago. I’m getting more and more similar to George Clooney :-)
I usually claim the huge workload for white hairs in front of my boss.
@Cath: My greys are the exact opposite, curly and kinky compared to my relatively straight brown hair. If they continue at this rate, I may end up looking a bit more like Professor Trelawney than Emmylou Harris.
@Sarbjit: Haha,yes! I will console myself with the thought that my aging hair follicles may just by the pathway to becoming a powerful wizard. Score!
@Viktor: Alas, if you’re starting to look more and more like George Clooney, I don’t think your boss will feel very bad for giving you so much work :)
I have white at the front, grey in the middle and brown at the back. My Dad always had a bushy, full head of hair which was white for the last 20 years of his life, and my mother’s hair never went grey – it stayed brown until the end. I suppose I am a hybrid.
Elizabeth, I just turned 27 myself and have found a few gray hairs as of late. So you are not alone (well, definitely not after reading the previous comments)! I am just hoping there is no truth to the myth that when you pull them out, you get two in that place.