A new gene study may help explain why she sees crimson, vermilion and tomato, but it’s all just red to him. In an analysis of the DNA of 236 men from around the globe, researchers found that the gene that allows people to see the color red comes in an unusually high number of variations. That’s because the gene, known as OPN1LW, sits on the X sex chromosome. Women have two X chromosomes, one from each parent, while men have one X and one Y chromosome. Because women have two different copies of the “red” gene, the fact that the gene can have so many variations means it may especially aid women’s perception of the red-orange spectrum.