Ho-o-o-okayyyy ... were one able to look at the cells, chromosomes, and DNA of a "fetus", one would see:
* The chromosomes and DNA are of a human, not any other animal or a plant;
* The DNA is not that of the mother, but of a unique human individual;
* The cells are alive;
* The cells are organizing, developing, and maturing into a complete human body, not an amorphous blob, or a part of an organ or limb;
* Barring violence, accident or early disease, a fertilized and implanted egg will organize, develop, and mature into an adult human;
* "Fetus" is a term for a developmental stage in the continuous process from fertilized and implanted egg through an adult dying of the infirmities and diseases of old age; a "fetus" by its nature is not a static, fully formed creature.
Thus, a human fetus is fully human from fertilization and implantation: the difference between a fetus and a newborn infant or an adolescent or an adult is one of maturity, not kind; there is no stage at which a fetus magically becomes a person, but a fetus is a stage in the maturation of the person.
Notice how many times I invoked Christianity or some other religion?
This DU member and DU folk like her do not lack the intellect to understand this, just the will. Their, "I want!" has overridden their, "I know."