If their dad gives them a y chromosome, they’ll be xy, or biologically male. It is often assumed that women have xx chromosomes and men have xy, but biology is more complex Some women have xy chromosomes — a natural variation in sex development They grow up identifying and living as women, and most only discover well into puberty that they are different. The egg always carries an x chromosome, but the sperm can carry either an x or a y chromosome If the sperm that fertilises the egg carries an x, the baby will have two x chromosomes (xx), typically developing as female.
In humans the sex chromosomes consist of one pair of the total of 23 pairs of chromosomes The other 22 pairs of chromosomes are called autosomes Individuals having two x chromosomes (xx) are female Individuals having one x chromosome and one y chromosome (xy) are male. Women have 22 normal chromosomes and 2 x chromosomes, ie 22 + xx, and men have 22 normal chromosomes and 1 x, 1 y, ie 22 + xy. Traditionally, females have two x chromosomes (xx), while males have one x and one y chromosome (xy)
