Male

The sex chromosomes are referred to as X and Y, and their combination determines a person's sex. Males have two distinct sex chromosomes (XY), and are called the heterogametic sex. Females have two of the same kind of sex chromosome (XX), and are called the homogametic sex. In humans, the presence of the Y chromosome is typically responsible for triggering male development; in the absence of the Y chromosome, the fetus will undergo female development. The XY sex-determination system is found in humans, most other mammals, some insects, some fish (guppies), and some plants (Ginkgo tree).