You used the word "capable." Now lets look at the definition of the word. Capable - Having the ability, fitness, or quality necessary to do or achieve a specified thing. Do you agree that once born, a fetus "becomes" a baby and can make audible sounds. If so, I can say that a fetus is capable of speech, consciousness, independent thought, freedom, and survival?The pain argument is commonly used by the pro-life movement because according to them, "the fetus can feel it". This of course is not true and I'd prefer to get it out of the way before the rage kid mentions it. Scientifically speaking, responding to stimuli is a required piece of criteria for something to classify as a biological organism. It is for that same reason that virus doesn't classify as life.[source] Feeling pain is an important point because until 20 weeks, the sensory systems and neural connections required to respond to stimuli are absent. Just like I stated above, most abortions occur in the first trimester, way before the age of 20 weeks.[source] Philosophically speaking, we can argue on what defines a human. A human being is something capable of consciousness and independent thought, freedom and survival, would you not agree? If there is one absolute fact in the universe, it is the fact that your own thoughts exist and that you are conscious of your own existence. A fetus cannot do this, not until the brain has sustain emotional reactions at week 24 anyway.
Not fully forming sections of your body is completely different than not feeling or thinking.
It isn't a matter of whether a fetus CAN do this or CAN do that, it is whether the fetus is CAPABLE of doing this or that. It is a well known fact that the fetus will be self-conscious, will have independent thought, etc.
If a fetus is capable or doing all of those, I can also say that an embryo is capable of the above as well, because an embryo is capable of becoming a fetus. In regards to the responding to stimuli aspect, the embryo is also capable of responding to the stimulation. The comparison to a virus is not a good one. A virus is a virus. That is it. An embryo changes, a fetus changes, a baby changes, a teenager changes, an adult changes, etc.
There are plenty of people in the world that cannot feel, paraplegics, people in comas, and others. I presume that you would agree that they are still humans. But they cannot respond to certain stimuli.