 In most cases, males are only one color (for instance, black) as they have only one X chromosome.Male calicoes can happen when a male cat has two X chromosomes (Klinefelter syndrome, with XXY sex chromosomes and generally sterile), is a chimera with two different cell types, or rarely when some skin cells of the developing kitten spontaneously mutate.Calico cats can also be lighter in color—"dilute calicos".