All the cells created from the cells that have not lost the Y chromosome will be XY.[8] The 46,XY cells will continue to multiply at the same time as the 45,X cells multiply. The embryo, then the fetus and then the baby will have what is called a 45,X/46,XY constitution. This is called a mosaic karyotype because, like tiles in mosaic floors or walls, there is more than one type of cell.