Humans have two sex chromosomes, the X and Y. Females have two X chromosomes, while males have X and Y chromosomes in their cells.
But one exception is that there are girls and women who have XY chromosomes.
This can happen when a girl has androgen insensitivity syndrome.
Females with XY karyotype with 46 chromosomes is a type of disorder known as swyer syndrome or XY gonadal dysgenesis.
This type of female lacks sex glands but has gonadal streaks, in which the ovaries do not develop properly, and are replaced by functionless scar tissue.
The reason for this syndrome is mutation in chromosomes.