You should ask yourself what you mean by "fully human." A pre-born child has a heartbeat at 4 weeks, fingers and toes at 5 weeks, brain waves at 6 weeks and an established pain sensory network at 20 weeks. The child has its own DNA, blood type and sex assignment.

If what you mean is that the embryo doesn't "look" fully human, then perhaps what you are not recognizing is that human beings "look" differently at one stage of their development than they do at others. A newborn looks different from a teenager. A toddler looks different than a elderly person. And a embryo looks different than a person in their 30s. But all are human beings and the only question that we have to decide is~ who gets human rights?

Who is it illegal to kill? What kind of human life would you say is "unworthy of life?"

"And here we come to the fundamental question in dispute; that question can be described in different ways: whether all human beings have a right not to be killed; whether membership in the human species is enough to confer rights; whether we accept the existence of a category of human non-persons. Opponents of abortion, embryo-destructive research, euthanasia, and infanticide believe that all human beings should be protected from being killed. They believe, further, that to the extent America fails to provide this protection it betrays its own founding principles. The party of death, on the other hand, believes that some human beings deserve that protection and some do not."

From the Party of Death, by Ramesh Ponnuru