The bottom line is, in the racing world, a âniceâ horse is not as important as a âwinningâ horse. Below: Mountain Horses must be certified for both gait and temperment before breeding, to ensure the best traits get passed on to the next generation.
Exceptions to these generalisations happen in the cases of XX males or XY females, or other syndromes. This system is in contrast with the ZW sex-determination system found in birds, some insects, many reptiles, and other animals, in which the heterogametic sex is female.
46, XY Intersex. The person has the chromosomes of a man, but the external genitals are incompletely formed, ambiguous, or clearly female. Internally, testes may be normal, malformed, or absent. This condition is also called 46, XY with undervirilization.