Use in clinical context
Only males have a Y chromosome, which is always inherited from their father. There are very few genes on the Y chromosome, but a crucial gene involved in determining biological sex – SRY – is found on this chromosome and not the X chromosome. It is possible for individuals to only have a single X chromosome – these individuals are biologically female as they lack the Y chromosome and the SRY gene that determines biological maleness. It is not possible for individuals to only have a Y chromosome as the X chromosome is essential to life and development.