Is it Possible to Have Three Biological Parents?

Elizabeth Marquardt at the Family Scholars Blog: Apparently, during gestation the embryo’s genetic markers are switched on and off in reaction to the environment experienced in the womb. In other words, the woman carrying the embryo physiologically shapes the resulting baby’s DNA, even if her egg was not used to conceive the child, and thus she can be said to be a biological mother of the child as well.