Human males are referred to as heterogametic. why?

Heterogametic:

1. The male produces two different kinds of gametes or sperms; half of the gametes have an X chromosome, and the other half have Y chromosomes.
2. In humans, females have 23 homomorphic pairs, and males have 22 homomorphic pairs plus a heteromorphic pair.
3. During meiosis, females produce only one kind of gamete all having one X chromosome so females are homogametic
4. The males produce two kinds of gametes, one with an X and the other with a Y chromosome therefore, the male is called heterogametic.