Colonizing Mars exposed the colonists to mutagenic radiation, causing people born on Mars to have birth defects (and psychic abilities). They weren’t native Martians, so the three booby lady won’t exist until we send people there.
Fun fact, the Earth has a magnetosphere that protects us from radiation, and Mars does not. So it is very likely that Martian colonists would experience higher rates of cancer, birth defects, and sterility even with physical shielding.
But also, even if a human were to grow a third booby, it would probably be above or below one of the normal boobies, along a vertical line called the “milk line.” A third medial booby is, medically speaking, unlikely.