content: Calico cats are almost always female. The color genes for red and black are on the X. So to make a red female you need two red X genes one from mom and one from dad. Dad is XY so he has one X only. The few calico or torbie /tortie males are usually XXY anomalies but in my breed there is one breeder with a strange calico male line that produces fertile males. The geneticists have been studying him but no idea how or why on that yet. You are correct though and wanted to add my 15 years breeding experience and 20+ genetics research "2 cents" =) Red and torbie were my specialty. Now I am sick to death of catty rival cat breeders so we will go back to my first loves dogs and I hope horses.