Going grey? Don't blame stress for the damage, as it's your mother and father's fault, says a new study.
Unilever scientists think family history has a far greater influence on the greying of a woman's hair than previously thought.
To reach the conclusion, boffins studied more than 200 identical and non-identical Danish twin sisters aged between 59 and 81.
From analyses, they found little difference between the greyness of the identical twins - who share the same genes.
But there was more difference between non-identical twins, whose genes differ, the study published in the journal PLoS One found.
The research also suggests that receding hair is linked to mainly genetic factors, reports The BBC.
Lead researcher Dr David Gunn said: "This study offers us a fascinating insight into the reason why women go grey and it certainly suggests that environmental factors are not as important as we once thought.
"The research indicates that irrespective of how stressful a woman's life is, there are greater forces at play which are more likely to cause her hair to grey."
Nina Goad, of the British Association of Dermatologists, said: "This means that for the majority of people, greying hair is not down to something you have done, but to genetic factors beyond your control, and that generally your lifestyle will not greatly impact on when your hair loses its colour."