I always cringe when I see people describe human relationships in biological terms, it hints at a feeling of reductiveness, or the applicability of all biological models to human behavior without taking into consideration massive societal differences and the change in attitudes and the emergence of new sexuality (see Japan's hikkikomori) even of the past few hundred years. It's the same sort of "analysis" that uses "breeding" to refer to when people have children. To top it off, the people using these terms to describe human phenomena are likely not even qualified in biological sciences, never mind anthropology, sociology or psychology.