Male tortoiseshell cats can also be chimeras and not have Klinefelter's. There is a beautiful male Maine Coon bred in a Texas cattery which is a chimera. I almost bought a kitten sired by him, but then the breeder thought that the kitten was actually a torbie instead of a tortie and white, which is what I wanted, so I bought my Dandi from another breeder. Her father is also a Regional Winner from the Mid-Atlantic region.
This cat is Regional Winner (RW) SGC Dawntreader Texas Calboy. He has an interesting story.
This is an excerpt from Cat Gazette which gives a good succinct explanation of Calboy's chimera condition.
RW SGC Dawntreader Texas Calboy:
"...Calboy is unique as an extremely rare fertile male calico, since most of the males who sport the coat color are incapable of reproducing. Only one out of 10,000 male calicos are capable of fathering kittens.
So how does a coat color associated almost entirely with female cats end up on a male, and why is the combination so rare? Calboy is a chimera, according to veterinarian Brittney Barton of HEAL Veterinary Hospital in Dallas..." And what is a chimera?
According to the article in Cat Gazette, chimeras have two sets of DNA, Barton said. Normally, “we have one embryo with two different, separate, fertilization incidents,” which results in non-identical twins, the veterinarian explained. “Where a chimera comes in,” Barton said, “that’s when non-identical twins merge...Male cats have X and Y chromosomes, while female cats have two X chromosomes. The X chromosome is responsible for coat color: With only one X, males can be either orange or black, but normally not both. But with two X chromosomes, females can be orange and black. A chimera like Calboy has three chromosomes — XXY — which is caused by an incomplete division of the male’s XY chromosome pair at the time of fertilization, according to the University of Miami. The unusual combination allows a cat like Calboy to develop a coat pattern and color combination that would be normally impossible for males.”
Calboy is even more special because he is FERTILE. His breeder, thinking he was XXY and therefore sterile, let him run around her breeding girls at will. When he was 7 months old, she started noticing several of her girls were pregnant, and the only male who had access to them had been Calboy. She had him tested and...he was fertile. As I said, I almost bought a beautiful kitten sired by him.
SGC Calboy 's honors include:
2019 Best Maine Coon in TICA's South Central Region.
2019 20th Best Cat in the South Central Region
2019 6th Best Long Haired Cat
Has Earned His Championship, Grand Championship, Double Grand Championship, Triple Grand Championship, Quadruple Grand Championship and his Supreme Grand Championship along with Regional Winner During his show career.