An XY girl refers to a person who has a 46,XY karyotype, meaning they have one X chromosome and one Y chromosome, which is the typical chromosomal makeup for males. However, due to a variety of genetic reasons, they develop female external genitalia and female gender identity. This condition is known as Swyer syndrome, which is classified as a disorder of sex development (DSD).
While individuals with Swyer syndrome have XY chromosomes, they lack a functional SRY gene, which is responsible for triggering the development of testes. This absence prevents the development of male characteristics, leading to the development of female external genitalia.
Swyer syndrome is a rare condition that can cause infertility. Individuals with this condition typically have no internal reproductive organs, such as ovaries or testes. They may require hormone replacement therapy to develop secondary sex characteristics and may choose to undergo feminizing surgery to complete their gender transition.
