"Human" refers to qualities of our species, homo sapiens, that make us different from other animals. Usually, it refers to those unique qualities as speech, complex reasoning, complex emotion, symbolic thought, and the like.

This refers to an aggregate set of qualities that exist in general across the population. Individual members of the population, however, may exhibit such qualities in varying degree -- or even not at all -- but still remain members of the population.

Thus, the child of a human mother is still considered human, even if she cannot speak. Or even if she cannot engage in complex reasoning. Or even if she cannot think symbolically.

Bwa ha ha haaaa!!