Answer:
genetics
Step-by-step explanation:
calico cats must also inherit a gene unrelated to the X and Y chromosomes that codes for white fur. Because male cats have one X chromosome with code for black or orange and one Y chromosome with no color genes, they cannot technically be calico. About one in every 3,000 calico cats is born a male, and, unfortunately, don't live as long as female calicos due to their genetic abnormalities. XXY Syndrome renders male calicos sterile and can be the root cause of many other health problems