Does it have its own DNA? Or does it have its mother's DNA (exclusively?
Most fertilized ova do not implant.
I realize that.
Life begins at fertilization. While a zygote (or a blastocyst) probably does not have feelings, it is a life. Whether that life is capable of feeling or not, it is a life. It is not man's (i.e., human's) place to interfere with the development of that life.
With that kind of reasoning, one could argue that any artificial means of preventing sperm from fertilizing an egg is verboten.
It seems better to prevent an egg from growing into a viable baby than to rip a growing baby from its womb by a mother that does not want it there.
DNA is not some mystical substance that confers properties of individuality or anything else. It's just a carrier of information used to direct biological processes. Identical twins or triplets do not have unique DNA--does that mean their lives are meaningless? The chicken I ate last night, the cells I grow in the lab all have unique DNA--does that give them some kind of special status?
Life begins at fertilization. While a zygote (or a blastocyst) probably does not have feelings, it is a life. Whether that life is capable of feeling or not, it is a life.
I cannot say that life "begins" at fertilization, because there is never a point at which life is absent. The living sperm fuses with the living egg to form a living zygote. They are alive, but they are not "a life". A couple of hundred cells do not have the physical capability to be aware. From a purely objective standpoint, I cannot see any significant or functional difference between a ball of a few cells resulting from a fertilization event and the cells coating the bottom of the Petri dish in the lab.
If two fertilized ova fuse and grow as one embryo, it does not make the resulting person into two lives--it is still just one person, one life. About three weeks after fertilization, when there is a sufficient number of cells to start forming a nervous system--which is the seat of all awareness--then, it is appropriate to consider the organism to be a separate person. Because, objectively, the nervous system is the distinguishing factor between a person and a bunch of cells.