What is a person?

Is life defined by the inherent qualities of being composed of organic and self-sustaining biology, or is it defined by the qualities that make up being human; being aware? Being alive? Life doesn't begin at conception. The gametes that produce the end-result of offspring were already living before conception. Everything from the bacteria feeding from the inside of your eyelid, to the newborn infant in delivery room 214, to Donald Trump, they're all equally alive. What is the cut-off point? If gametes aren't human, and a fetus isn't human, does the classification of "human life" really matter? This cutoff point seems rather subjective as it varies from person to person. If "being human" means to possess emotion alongside intelligence and consciousness, then I feel that many things will eventually fit this definition aside from those who are biologically human, as time passes.

And at that point... would those entities receive the same protections that we as humans give ourselves? And if not... why not?