An egg or a sperm doesn’t have the innate ability to develop into a complete human being, an embryo does. If it is kept alive it will inevitably develop a brain, brainwaves, consciousness, all that because it is a human being, and these are qualities of a human being. Just because they are temporarily inactive does not change the fact that it is a human being: if someone is temporarily in a coma, are they not a human being? Just because they are not manifesting all their potential as a human being at any given time, does not mean they are not human. A child cannot reproduce - reproduction is one of the criteria for life - does this mean a child is not alive? No, a child is a human being, and a human being can reproduce when it is mature enough. Human beings have the potential to create art - does this mean that those who are not creating art at this moment are not human? Are people who are asleep not human? Or is a living being more than it’s state in a static moment - is it everything it will be over its lifetime?