The XY sex-determination system is the sex-determination system found in humans, most other mammals, some insects (Drosophila) and some plants (Ginkgo). In this system, females have two of the same kind of sex chromosome (XX), and are called the homogametic sex. Males have two distinct sex chromosomes (XY), and are called the heterogametic sex.
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.
There is also a temperature-dependent sex determination system is found in some reptiles.
Read more about XY Sex-determination System: Mechanisms, Recent Studies On The Genetic Factors That Influence Gender Traits
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