A blastocyst is not a human being, only a bunch of cells. ….Quote the Economist
Scientifically speaking everything that is needed for the functioning cells to one day be the President of the United States, is already programmed within these cells.
It’s on science alone you loose your argument, other than the moral implication of taking the life of an organism that is destined to walk, talk, act, react, and rationalize…with thumbs. This is indeed a “human” and this human is at it’s most primary form of development.
We don’t stop with the development after we are born, we don’t stop with development even at our age, because the cells of our organs are aging as we write these words. There is no scientific method to halt this aging process, it was deigned into us as zygotes, and embryos.
So get with the program!~This is simply one stage in your development when you realize that even at our ages, it’s programmed within us that we maintain the capability to learn. Adaptation began in the womb.