WHY DOES HAIR TURN GRAY?
Despite what your parents may have told you, it's very unlikely that you caused their gray hairs. Severe trauma or some medical conditions have been known to "put snow on the roof", but scientists have yet to link rotten children to the phenomenon. In most cases, the real culprit is Father Time.
"Melanocyte" cells are the magic ingredients that give hair its wide range of colour - from lightest blonde to darkest blonde. But by our mid-twenties, the melanocytes become less active. Hairs begin to emerge from follicles with less pigmentation, causing them to look gray. When melanocytes stop working altogether, the hair grows with no pigmentation, just the white colour of its original protein.
Source : Why In The World? : Reader's Digest
Kind words will unlock an iron door : Kurdish Proverb