Actually what the article is saying is that redheads may be at an even greater increased risk of developing melanoma than non-redheads due to the combined effect of phenotype and genotype, over just the risk of phenotype (fair skin). The genotype of a redhead which leads to the fair/skin, freckling, and red hair, is the result of having 2 copies of the recessive mutant melanocortin receptor gene that results in the predominant expression of pheomelanin (red-yellow melanin pigment) over the dominant, more prevalent, gene that codes for eumelanin (brown-black melanin pigment) which is the predominant form of melanin in skin, hair, and eyes worldwide. What the study indicated was that pheomelanin provides poor protection to the skin from UV radiation, but that in addition, pheomelanin has a greater capacity to generate reactive oxygen radicals that may be carcinogenic than does eumelanin. For example, in the study described, red mice had a much higher incidence of melanoma than did albino mice (with complete lack of pigment), even in the absence of UV radiation.