Male Tortoiseshell Cat Defies the Laws of Biology

More on PawNation: male tortoiseshell kitten, MaleTortoiseshellKitten, tortoiseshell cat, TortoiseshellCat
Male Tortoiseshell Cat picture

"Don't call me no stinking girl!" Photo: Masons News Service/

A gender-bending kitten in England is grabbing headlines for its unusual markings -- and more notably, his sex. Eddie, a black and orange tortoiseshell kitten, was born male -- a "genetic impossibility," his owner, veterinarian Karen Horne, told the Daily Mail. Horne adopted the unusual male kitten after it arrived -- along with his three tortoiseshell sisters -- at her veterinary practice via a local cat rescue group.

The Daily Mail writes that the cat "overturns the normal laws of biology," and that's somewhat true. Tortoiseshell cats are nearly always female because two X chromosomes are required to produce the brindled black and orange coat coloring. Male cats have only one X and one Y chromosome, so it is "technically impossible" for them to inherit the tortoiseshell coloring, the Daily Mail writes. However, in extremely rare instances, a male kitten is born with tortoiseshell markings because it has an extra X chromosome (making it an "XXY"), according to

Just how rare is a male tortoiseshell cat? "Of eight million pet cats in Britain only a couple a year are born male tortoiseshells," reports the Daily Mail. At, they estimate the odds at 1 in 3,000.

Eddie the kitten, named for the famed cross-dressing British comedian and actor Eddie Izzard, may be a "boy dressed in girls' clothing," his owner told the Daily Mail, but "so far, there are no signs of any gender confusion and he seems to be all there."

Add a Comment

*0 / 3000 Character Maximum


Filter by:

Why is the Tortoiseshell not a breed on your list of cats? I'm a proud owner of one, and they are VERY loyal, which begs to ask, where are they on your list of breeds?

April 13 2013 at 11:51 AM Report abuse rate up rate down Reply
Kristen Hensley

I have a black and orange Tortisshell kitten male. DEWY is 1 in 3,000 according to His twin did not make it the first week. If you are interested feel free to contact me.

November 16 2012 at 12:43 PM Report abuse rate up rate down Reply

My Chicago born red tabby male cat's father was a very virile tortoise shell & most definitely not sterile or girlie!

October 21 2012 at 11:12 AM Report abuse rate up rate down Reply

Who is Cutest?

Like us on Facebook?