I really do believe life derives from life. Sperm and ova are alive, and a zygote, blastocyst, embryo, and fetus are alive unless they die, and they, too, can die. I see zygotes, morulae?, blastocysts, embryos, and fetuses as human organisms. However, embryos and fetuses really live only in attachment to women's live bodies. If a woman dies at or after the fetus is viable, however, it could be removed and would be a living born child. However much artificial aid is needed for it to continue to live, it can do that without a biological connection to a woman's bodily life. Life has at that point successfully derived from life, so that there are two distinct lives.
That I think this way has to do with not thinking the unique DNA of conception is as important as others do, for various reasons. First, no matter what DNA you have, if your life depends biologically on a specific other organism's life, your life is derivative. A human zygote or morula or blastocyst can get nutrients in a petri dish or, in a woman's body, from her body without implantation, so at this stage, that organism has short life of its own that does not derive from a woman's biological life, no question. But a blastocyst/embryo in a petri dish cannot live very long without that direct connection, and we do not know why. Something more than nutrients is derived from her life. This would be the case whether the DNA was unique or cloning occurred using the same DNA.
Second, DNA can contain defects that result in all sorts of deformations and diseases, but advances in genetics have allowed us to identify some of these problems, and the day will come when it will be possible as part of medical treatment to alter DNA to eliminate those problems. Will an organism's DNA being therapeutically altered change that organism into another organism? Would it change that organism's life into another organism's life?
If a woman carries a pregnancy to term and gives birth, the leakage of fetal and maternal cells and DNA across the placenta means that one can find different DNA in the woman's blood thereafter, and that the fetus gets DNA from the woman, too. This fetal-maternal microchimerism can occur even if the woman had implanted a fertilized ovum that was donated and had none of her own genetic contribution. Does this mean the woman is a different person, that her organism is a different organism? Does it mean that the embryo is now genetically unrelated to the ovum donor? I don't think so. An organism whose DNA is altered is still going to be the same organism, and a born person whose DNA is altered is still going to be the same born person.
On the other hand, if the biological life of one organism depends for its continuance on the biological life of another organism but not vice versa, then the the dependent organism's continued life is being derived from the other organism's life. That doesn't have to do with how unique one's DNA is, nor does it negate the fact that the organism is indeed an organism. But if you do not have the right to derive continued life for your body from my body, why would we make the claim for anyone else, born or unborn? Each one has a right to the life one can have without getting some from somebody else's life.
When a fetus attains viability, it can continue its own life without using someone else's bodily life. That is the capacity to be a live human being or person. Even if it has not yet developed all sorts of stuff necessary to have the sort of mental life that we associate with a person, it is not relying on a particular biological organism's life for the capacity to develop that stuff.
and I have 2 kids of my own. 