Red hair color in humans is inherited as an autosomal recessive trait in a family where both parents had dark hair and

Red hair color in humans is inherited as an autosomal recessive trait in a family where both parents had dark hair and a red-haired child was born. The grandparents on both sides were dark-haired too. How to explain this fact and extinguish a possible conflict in the family?

This is due to the fact that distant relatives or ancestors had red hair and this gene was passed from generation to generation (but did not manifest itself). To extinguish the conflict, you can take a DNA test.