QUICK FACTS
No. This is a common misconception. Ginger cats can be either male or female although ginger females are less common.
The genetics of ginger is explained in more detail in Tortoiseshell and Tri-Colour Cats (ginger is caused by the same gene as tortoiseshell), but this is a short version for those wanting a quick answer.
The ginger gene changes black pigment into a reddish pigment. The ginger gene is carried on the X chromosome. A normal male cat has XY genetic makeup so he only needs to inherit one ginger gene for him to be a ginger cat. A normal female is XX genetic makeup so she must inherit two ginger genes to be a ginger cat. If she inherits only one ginger gene, she will be tortoiseshell with some ginger areas and some black/brown areas.
The ginger gene is called a sex-linked gene because it is carried on a sex chromosome.
Also, if you look closely, ginger cats have tabby markings though these may be faint or only visible on the face, tail and lower legs. They are also visible in the ginger areas of tortie cats. This is because the gene that turns off tabby to give solid colour cats does not work on the ginger colour.
ARE GINGER FEMALES RARE?
No. They are less common than ginger males, but they are not rare. It is possible to selectively breed ginger female cats by mating ginger males and ginger females together. They will have ginger offspring.
ARE GINGER FEMALES STERILE?
No. They are just as fertile as other female cats!
IF THE GINGER CAT HAS WHITE MARKINGS, DOES THAT INCREASE THE LIKELIHOOD IT IS FEMALE?
No. This myth was sadly propagated in a British cat magazine that should have known better! White spotting is not sex linked. It isn't related to the cat's gender and it cannot influence the cat's gender. The relative frequencies of ginger-and-white males and females is the same as ginger-without-white males and females.
ARE TORTOISESHELL AND CALICO CATS ALWAYS FEMALE?
No. Though they aren't very common, tortoiseshell and calico males occur more often than most people realise and more of them are fertile than people realise.
The genetics of tortoiseshell males is explained in more detail in Tortie Tomcats, but this is a short version for those wanting a quick answer.
WHAT CAUSES TORTIE AND CALICO TOMCATS?
The most common cause seems to be chimerism. Two embryos bump into each other in the womb and merge together. If one is black and the other is ginger and one or both are male the result may be a tortie tomcat (or calico tomcat if the embryos had white patches).
The next most common cause seems to be XXY genetic makeup (Klinefelter Syndrome). An embryo gets one X chromosome with the black gene, one X chromosome with the ginger gene and one Y chromosome that makes it male. This chromosomal abnormality used to be thought the most common cause, but recent research shows chimerism is probably more common.
The third cause is somatic mutation. A ginger male embryo devlopes black patch in the same way as some babies develop port wine stain birth marks.
ARE TORTIE AND CALICO MALES ALWAYS STERILE?
No. It depends on which of 3 conditions has caused their colouration.
Those with XXY makeup are infertile and often have other physical abnormalities due to having too many copies of some genes..
Those with chimerism are fertile but they can only pass on either the ginger colour or the black colour, but not both, to their offspring.
Those with somatic mutation are fertile because the black patches are just birthmarks.
ARE TORTIE AND CALICO TOMCATS VALUABLE?
No, but people who advertise them as "rare" would like you think so!
Because they are either sterile or they only pass on either ginger or black to their offspring, they are no more valuable than any other cat (value will also depend on what breed it is). Some superstitious people think they bring good luck.
Most white cats are not albino. Albino means a total absence of pigment. Albino cats will have pink eyes or very, very pale blue eyes.
No. There are several genes that cause the white coat colour. Only some white cats will be deaf.
The genetics of white cats, blue eyes and deafness is explained in more detail in White Cats, Eye Colours and Deafness, but this is a short version for those wanting a quick answer.
Pure white cats with blue eyes are more likely to be deaf than white cats with green, yellow or orange eyes. They have the Dominant White gene which can affect the way the inner ear develops.
Pure white cats with one blue eye may be deaf on that side.
White cats with tiny smudges of colour, or which had tiny smudges of colour when they were kittens, are less likely to be deaf because the white colour is caused by a different gene called White Spotting.
White cats that have Siamese ancestry are less likely to be deaf because they have the "Siamese Blue Eyes" gene (a type of albinism) which isn't linked to deafness.