46,XX/46,XY is either a chimeric or mosaic genetic condition characterized by the presence of some cells that express a 46,XX karyotype and some cells that express a 46,XY karyotype in a single human being.[1][2][3] While some individuals with this condition may be classified as intersex, others may have typical male or female characteristics.
The presence of both 46, XX and 46, XY cell lines in a person is known as either chimerism or mosaicism. A chimera is an individual with two or more cell lines derived from different zygotes. In mosaicism, on the other hand, two or more cell lines come from the same zygote as a result of non-disjunction during mitotic division.
The vast majority of these cases are the result of contamination by maternal cells in an otherwise normal male fetus. Occasionally, the presence of 46,XX and 46,XY cell lines are true chimerism or mosaicism … This result is more suggestive of mosaicism
It indicated that all three X chromosomes in both fetal cell lines are of maternal origin. This result is more suggestive of mosaicism, since, by definition, the 46,XX cell line in a chimera originates from a normal female zygote and must have one paternal X chromosome.