What causes grey hair and what can be done to avoid it?

I'm talking for someone in their 30's.What causes grey hair and what can be done to avoid it?
genetics, there is nothing you can do to avoid it. only color it.What causes grey hair and what can be done to avoid it?
Gray hair is caused by lack of pigment in the hair or an easier way to say it lost of color in the hair but there is noway to avoid it it just happens but what you can do about it is get a color that has a color base or blue red and yellow a good way to get this color back is to try framesi's hair color product i hope this helps
stress causes grey hairs, try to be worry free and get rid of things in your life that stress you out.
It's in the genes CAN'T avoid it
It is a genetic thing. It is also something that happens to pretty much everyone. It is a SAD part of growing older. Mine started in my late 30's and now I am about 50 percent gray. You can either get use to it or color it. The only way to avoid it is to die and that is definitely NOT an option. My advice is, as long as you are a healthy happy person, hair color shouldn't be that big of a problem. Live, love and laugh!!!
The cells that give your hair its color just run out of pigment. There really isn't much you can do to avoid it, just color it and cover it up if it bothers you.
Hair grows white when the color pigment (melanin) ceases to be produced in the hair follicle and small air spaces take its place. Please check out http://useinfo-grayhair.blogspot.com/ for more info.