see you also have to have the genes in your family remember high school biology with the genetic chromosomes and stuff like how if it's XX one result occurs and if the result is XY then another (I cant fully remember but thats the male and female determining one right?) well you have dominant and reccessives called something in french cant remember alle something well the one for red hair is always, always, always the reccessive so ever wonder if both your parents are brunettes or blondes or black haired and your red haired look to your granparents seeing as one of them from each side of the family will be red haired back to the X and Y explanation:

in this X = any colour but red Y = Red

result one - XX - no red

Result two - XY - not red but the gene is there their kid could be red haired

Result three - YX - same as above but other way round still not red

Result four - YY - Red haired person

to be red haired both of your parents or grand parents need to be carrying the Red hair gene.