It exhibits life signs from the moment of conception. What would you call that splitting of the egg cell after fertilization? There is a complexity of things happening at that very moment. Things science still doesn’t understand. Predetermined assignments through instructions from DNA start telling every cell where it’s supposed to go and what it’s supposed to do. It’s not a random event; everything is predefined through DNA. THAT IS WHAT WE CALL LIFE. Life isn’t just the mass of flesh, organs, and blood as a collective to make up a species. Life is the process that occurs on its own in a predetermined manner from the very beginning of conception.
Excuse me, but an unfertilized oocyte exhibits life when it is alive and does not exhibit life when it is dead and the same thing is true of sperm. Some oocytes begin to grow and mature, and others die by atresia. Only live oocytes can be used for zygote formation, and if they are dead, zygotes do not form.
Yes, I agree that a zygote is alive, and a blastocyst is independently alive, unless it dies. But all mammalian zygotes/blastocysts have a very short natural independent biological life span. We know this from scientific experiments.
A mammalian blastocyst in a petri dish with oxygen-rich nutrient of the strength available in the mammalian uterus lives independently there for as long as it lives in the uterus prior to implantation - the length of time depends on each species, and for the human blastocyst, it is 8-10 days.
But the most powerful scientific supernutrient known will keep a mammalian blastocyst alive long enough to double the preimplantation life span. We only know this from experiments with non-human blastocysts, because it is illegal to grow a human blastocyst in a petri dish for longer than 14 days, but it can be extrapolated that the doubling would be the same for human as for other mammalian blastocysts.
No experiment has seen even one mammalian blastocyst continue living beyond the doubling of the preimplantation life span. They all die. By extrapolation, then, the natural biological life span of a human blastocyst in a petri dish with the most powerful scientific nutrient known can be 16-20 days. But that is shorter than the duration between a woman's menstrual periods. Hence, in the woman, even if that nutrient were in the uterus and could double the human blastocyst's lifespan, the human blastocyst would die before being flushed out in menstruation.
This means that, like all other mammalian blastocysts, the human one can only live in biological independence as a blastocyst and then die. It cannot go through organogenesis and further development without implantation in the woman's body.
Thus, the development of the phenotype of a member of its species does not occur based only on the genotype, i.e., the DNA. It occurs because the blastocyst is implanted into a body of that species already exhibiting that phenotype and, as an embryo, lives as a part of that body, receiving oxygen and nutrients and antibodies from that body's blood, which is how that body's organs and limbs live, save only that, in the case of the embryo, a placenta is needed for this reception.
On one hand, if the placenta+embryo becomes biologically disconnected from the endometrial tissue of the body involved, it immediately dies. On the other hand, if the placenta+embryo stays biologically connected to the endometrial tissue but the body of the female dies, the placenta+embryo dies. The same thing is true for the placenta+fetus up to the point where development has been sufficient for viability outside the body. There are no exceptions to this. Viability of the individual fetus depends on sufficient development to be able to breathe oxygen instead of taking it in from the blood circulating in the live body of the female. If that is attained, then even if the female dies, as long as the fetus is removed quickly enough, it will survive.
To me, all that means is that, though a zygote/blastocyst has a short independent biological life span of its own, it is incapable of developing into a phenotypic member of its species without living for a significant period of time as an actual part of the body of a live phenotypic member of its species. During that period of time, it is part of that larger body, not a biologically independent individual, and we can't grow it in biological independence of that larger body.
To me, it is obvious that the woman with no zygote formed is just a human female biological unit. The woman with a zygote formed or a blastocyst growing but not implanted is just a human female biological unit with the potential to become pregnant if implantation of a live blastocyst occurs. The pregnant woman is a woman in whom implantation has occurred and is therefore a woman+placenta/embryo biological unit. There is no separate "life of the embryo." All of the life involved after implantation is the woman's life, and the embryo is part of the woman's body and has continued life just as the woman's limbs and organs have continued life.
Why should it not make a difference that the DNA of the embryo is different? Because when a person receives an organ transplant, the transplanted organ has different DNA, but the only reason it does not die is that it is functioning as a biological part of the recipient's live body.
To me, this is the meaning of the Biblical saying that children are "the fruit" of the woman - they are to her as apples are to an apple tree, regardless of the fact that the zygote could not form without the spermatic contribution, and when they are sufficiently ripened, they come out of her body and are separate from it.
What is predetermined for the biologically independent mammalian blastocyst is death as a blastocyst. Without becoming part of the woman's body, it could never have the phenotype of a member of the human species, let alone live as an equal member of the human species.
Living as an equal member of the human species means living in biological independence from that woman's body, and that is what the Supreme Court majority opinion meant by "meaningful" human life.
