Why is human male called heterogametic?

Human males are referred to as heterogametic because they possess two different types of sex chromosomes: one X chromosome and one Y chromosome (XY). In contrast, females have two X chromosomes (XX) and are termed homogametic. The presence of both X and Y chromosomes in males leads to the production of two distinct types of sperm, one carrying the X chromosome and the other carrying the Y chromosome, which determines the sex of the offspring. This distinction in chromosome composition is what defines males as heterogametic.