if you are a human organism, you possess dignity, not because I grant it to you, but simply because you are a human being
And therein lies the problem—the claim that embryos are equivalent to human beings at any or every other development stage—a claim which I and many others find to be simply laughable.
All pro-life conclusions are based on the foundational belief that a human life begins at the time of fertilization of the ovum. Thus, an embryo is viewed as a human being with all of the rights of an adult. Experiments which subject an ovum to any significant risk are the ethical equivalent of the infamous medical experiments that were inflicted on unwilling and uninformed victims in Nazi death camps. Ends do not justify the means. Thus, no matter how helpful to mankind embryo research might potentially be, it cannot be done if the embryo is eventually killed or subjected to a significant risk.
Their bizarre interpretations would also raise all sorts of other problems, such as with fertility clinics and the hundreds of thousands of embryos they create, or with taxation and claiming dependents—you name it. But their arguments are really just faith-based, and grounded in ignorance, not science, like most of their positions. On the other side:
At this early stage of development (before 14 days) the embryo does not have human form or genetic uniqueness. It is a growing collection of cells which can divide into two and naturally produce identical twins. It is unable to survive outside of the womb, does not have any organ structures including even a primitive brain and it has no degree cognitive development. After conception following intercourse some 60 percent of human embryos are discarded by nature at this stage of development, before the mother ever realizes that she was pregnant. It would be difficult for society to ascribe “rights” to something that has such a high natural mortality.
I find all of that to be entirely reasonable and rational, which is probably why the pro-life crowd doesn’t want anyone talking about it in the first place.
Second, the citation posits that because the very young embryonic human being can twin. But this does not prove that the embryo is not a human being. The fact that an identical twin can originate from a pre-existing embryo does not mean that that embryo wasn't a human being. While most human beings originate when a sperm fertilizes an ovum, some human beings originate later, in the process of twinning. Again, there is nothing here which demonstrates that an embro prior to 14 days of age is not a human being.
The citation then offers some standard objections to the humanity of the embryo: it cannot survive outside the womb; it doesn't have any organ structures; it doesn't have a brain; it has no cognitive development. None of these ultimately holds water. The fact that an embryonic human requires a particular environment to survive is no different than the fact that an adult human requires a particular environment to survive. If you put me in under water without a breathing apparatus, I will die. Does that mean I wasn't human? Of course not.
Regarding organ structures: why are they essential to what it means to be human? There are obviously some of us who lack certain organs... are we not human? What is it about organs that make there existence essential to being recognized as a human being? In fact, our organ systems serve to keep us (the individual human being) alive; that is their purpose. The youngest human beings -- embyros -- do not yet require complex organ systems to sustain themselves.
A similar argument demonstrates the irrelevance of the presence of the brain. The fundamental purpose of the human brain is to coordinate and integrate the various organ systems of the human being, such that the human being is a single, integrated organism. Again, the human being at the embryo stage is not yet so complex that he requires a brain to integrate himself.
Cognitive development could plausibly be proferred as a criterion for personhood, but it has no bearing on the fundamental fact that human embryos are human organisms. The author cited by Pb apparently believes that being a human organism is insufficient, and that some cognitive development is necessary to be deemed morally worthy, but -- once again -- no argument for this position is presented.
Finally, the citation asserts (without reference) that 60% of human embryos die at this early stage, and posits that therefore the embryo must not have rights. Even if the statistic is accurate, the error of this position is easily seen by noting that the mortality rate of adult human beings is 100%, yet we do not deny that they have rights.
So in this comment and its citations, we seem to have a number of unproven assertions. Perhaps Pb or someone else who agrees with him could prove some of these assertions in the comments.