A partial molar pregnancy occurs when an egg with genetic material is fertilized by two sperm. It causes the development of ...

From about weeks three to eight of pregnancy ... In partial molar pregnancies, the embryo has too many chromosomes (69 instead of 46) because the father’s chromosomes are doubled — there ...

they have 23 chromosomes inherited from the father and 23 chromosomes inherited from the mother, just like a normally developing pregnancy, leading to the name “biparental” CHM (see Figure 2 above).