Disorders of Sexual Development of Cats

Dr Rob Foster

University of Guelph

Person unfamiliar with the nomenclature of Disorders of Sexual Development (DSD) are advised to review the general section on DSD.

Chromosomal DSD

The male tricolored or calico cat is a well known Disorder of Sexual Development. To achieve 3 colors in a cat requires 2 X chromosomes. Most male Calico cats are XXY or another combination of multiple X and a Y.

The seminal paper is by Benerski

A typical example is reported by Pedersen et al (2014). They correlated chromosomal analysis (39 XXY) with testicular histology. They called the lesion degeneration instead of hypoplasia.

Balogh et al (2015) report on a cat with X/XY mosaicism. The male phenotype cat had cryptorchidism and persistent mesonephric (Mullerian) ducts.

Szczerbal et al (2018) reported on 3 cats with chromosomal abnormalities. There was an XX/XY chimera, a trisomy XXY tortoise shell male cat, and an XY cat with small testes, bifid scrotum, rudimentary penis and no uterus


Balogh O, Berger A, Pieńkowska-Schelling A, Willmitzer F, Grest P, Janett F, Schelling C, Reichler IM. 37,X/38,XY Mosaicism in a Cryptorchid Bengal Cat with Müllerian Duct Remnants. Sex Dev. 2015; 9: 327-332.

Pedersen AS, · Berg LC, · Almstrup K, · Thomsen PD. (2014) A Tortoiseshell Male Cat: Chromosome Analysis and Histologic Examination of the Testis. Cytogenet Genome Res. 2014; 142: 107-111.

Szczerbal I, Krzeminska P, Dzimira S, Tamminen TM, Saari S, Nizanski W, Gogulski M, Nowacka-Woszuk J, Switonski M. Disorders of sex development in cats with different complements of sex chromosomes. Reprod Domest Anim. 2018






Knighton (2004) reported on a cat that had a penis, prepuce and scrotum, but no intrascrotal testes. Abdominal surgery was performed for gonadectomy, but ovaries, uterine tubes and uterus was found. There was also epididymis and ductus deferens. The cat was 38 XX. The cat was subsequently found to have congenital adrenal hyperplasia and 11Beta hydroxylase deficiency.

Knighton EL (2004) Congenital adrenal hyperplasia secondary to 11beta-hydroxylase deficiency in a domestic cat. J Amer Vet Med Assoc 225: 238-241.


Normal gonads - XY Testicular DSD

Persistent paramesonephric (Mullerian) ducts (Uterus masculinus) - deficiency in Antimullerian hormone or receptor

This is a common anomaly in male cats. The paramesonephric ducts, those ducts that, in the female, would give rise to the uterine tube and uterus, are retained. In dogs this is called the persistent mullerian duct syndrome (PMDS). Affected cats are gonad and phenotypic males, but have a persistent paramesonephric duct. This can be found parrallel to the ductus deferens and also beside the epididymis.

Persistent paramesonephric duct (uterus masculinis) in a male cat. The inner two ducts have a uterine appearance, whereas the outer ducts are ducti deferentes.

Persistent paramesonephric duct in a male cat. The tube on the left resembles a uterine horn and the tube on the left is the ductus deferens. (YB135279).

Schulman and Levine (1989) reported a 10 month old castrated male cat with pyometra of a cystic uterus masculinus. It was a cryptorchid as the gonads were inguinally retained.

Vallefuoco et al (2013) reported on a 3 month old kitten with an anovaginal fistula, cloaca with vaginal but testes and an XY genotype.



Schulman J, Levine SH (1989) Pyometera involving uterus masculinus in a cat. J Amer Vet Med Assoc 194: 690-691.

Vallefuoco R, Alleaume C, Jardel N, Maenhoudt C, Cordonnier N. (2013) Type II atresia ani associated with rectovaginal fistula in a male pseudohermaphrodite kitten. Canadian Vet J 2013; 54: 475-478.


Milwright and Smith (1999) report finding a cat with 3 testes.

Roca-Ferrer et al (2015) reported on a cat with 4 intraabdominal testes. They were bilateral and close to each other on each side. Each testis had its own epididymis and epilateral deferent ducts fused to form one duct.


Milwright RD, Smith KC. Polyorchidism in a cat. Vet Rec. 1999 Dec 4;145(23):679-80.

Roca-Ferrer J, Rodríguez E, Ramírez GA, Moragas C, Sala M. A rare case of polyorchidism in a cat with four intra-abdominal testes. Reprod Domest Anim 2015; 50: 172-176.


Disorders of androgen synthesis or action

There are many reports of male feminisaton in cats.

Meyers-Wallen et al (1989) examined one such individual in detail and determined that there was a testosterone receptor problem and that this was an X linked heritable disease.

Hakala (1984) reported male pseudohermaphroditism in a 3 year old cat. The owner reported that the cat had been castrated, but it had a vulva and a penis that could not be extruded and was 3 mm long. No gonads were found and the karyotype was unknown.

Meyers-Wallen et al (1989) reported on a phenotypically female cat with gonads in the location of the ovaries, but no tubular genitalia. The gonad was testis and the karyotype was 38 XY. Based on fibroblast cultures, there was no testosterone binding to receptors.

Bredal WP, Thoresen SI, Kvellestad A, Lindblad K. (1997) Male pseudohermaphroditism in a cat. J Small Anim Pract. 38(1):21-4.

Hakala JE. (1984) Reproductive tract anomalies in 2 male cats. Modern Vet 65: 629.

Meyers-Wallen, VN, Wilson JD, Griffin JE, Fisher S, Moorhead PH, Goldschmidt MH, Haskins ME, Patterson DF (1989). Testicular feminization in a cat. Vet Med Assoc 195: 1456-1458.

Abnormal gonads

XY ovotesticular DSD

Schlafer et al (2011) reported on a cat that was phenotypically male with penis and scrotum, but had ovotestes in the location of the ovaries. It had both male and female tubular genitalia. It was typed as an 38XY, SRY positive.


Schlafer DH, Valentine B, Fahnestock G, Froenicke L, Grahn RA, Lyons LA, Meyers-Wallen VN. (2011) A case of SRY-positive 38, XY true hermaphroditism (XY sex reversal) in a cat. Vet Pathol 2011, 48: 817-822