“A human being is a biological category, and can be defined by human DNA, it seems to me. The category, person, is not biological, and maybe your teacher is confusing “human beings” with “persons”. All human beings need not be persons. For example, small infants are not yet persons. “Person” is a legal and social category. And all persons need not be human beings. For example, Mr. Spock (of Star Treck) was not a human being (he was part [Vulcan]). But he was certainly a person.”
That seems to me to be just right.