"I am so sick of being told what to look like," Martha says, insisting that it's important for women to take control themselves. "I don’t think women have suddenly lost any taboo or shame of grey roots. Growing them out takes profound bravery that often doesn’t go unnoticed (for better or for worse), but what I’ve found to be more powerful than any negative words, is the ability to look in the mirror and be able to see myself, not a version of me others have told me to construct." Katie Petersen, 34, from Portland, Oregon, agrees. Having decided to stop colouring her hair a year and a half ago, she now rocks a neat brown bob streaked with silver. "I know it’s hard not to worry what others think, but ultimately do what feels right for you. Nobody really cares about your grey hair as much as you do."