Aren't calico cats an interesting thing?? LOL LOL Amberlee is absolutely right. The calico coat color is caused by a coat color gene on the X chromosome, and needs two X chromosomes to appear. Since females have 2 copies of the X chromosome and males only have one, the calico pattern is seen most often in females. However, male cats have been seen with calico coloring because something goes wrong during fertilization or the early stages of fetal development and the fetus winds up with two X-chromosomes and one Y chromosome. This is very uncommon these individuals would most likely be sterile.

The same is true for the idea that most orange/yellow cats are males. The gene for the orange color is located on the X chromosome. Female cats have two X-chromosomes. In order for a female cat to be orange, she has to have the dominant gene for orange on both X-chromosomes. But any male cat who gets an orange gene on his single X chromosome will be orange. So when you see an orange cat, it is a pretty good bet that it is a male cat. About two thirds of them are male. Only one parent had to be orange, whereas to make a female cat orange, both parents had to be orange.

I'm with you, Amberlee. I find genetics fascinating, and studied it in school too! LOL