Generally calico male cats suffer from Klinefelter syndrome and have two X chromosomes. The abnormality of the 23rd pair of chromosomes causes their genetic map to be XXY, which is the reason why they are infertile and have a small number.

Cats have eighteen pairs of autosomes and one pair of sex chromosomes. The black and orange genes of our common calico cats are located on the X chromosome. Since its background color is white, the two X chromosomes are different in cats. Parts of the body are randomly deactivated, which is the origin of the calico cat (please see Wikipedia's description of "Barr's body", the mosaic is very clearly stated)

So, if you want to show three colors on your body, a cat must have at least two or more X chromosomes. The sex chromosomes of male calico cats are XXY, or a chimera is formed during development (two abnormal fertilized eggs are called a chimera), then the sex chromosomes of male cats will become XX/XY or XY/ XY.

No matter which one it is, it is caused by a rare chromosomal abnormality. For example, XXY male cats will not only show some female behaviors, but because the sex chromosomes are trisomic, they cannot divide symmetrically to produce normal sperm. Therefore, the number of male calico cats is extremely small, and the vast majority of them are sterile.

Generally calico male cats suffer from Klinefelter syndrome and have two X chromosomes. The abnormality of the 23rd pair of chromosomes causes their genetic map to be XXY, which is the reason why they are infertile and have a small number.