Similar biological denialism exists about nearly any observed difference between human groups, including those between males and females. Unfortunately, students push back against these phenomena not by using scientific arguments, but by employing an a priori moral commitment to equality, anti-racism, and anti-sexism. They resort to denialism to protect themselves from having to confront a worldview they reject—that certain differences between groups may be based partly on biology. This denialism manifests itself at times in classroom discussions and in emails in which students explain at length why I should not be teaching the topic.
To my surprise, some students even objected to other well-established biological concepts, such as “kin selection,” the idea that, when individuals take actions for the benefit of their offspring and siblings, they are indirectly perpetuating their own genes. Startled students, falling into what we call the “naturalistic fallacy”—the notion that what occurs in nature is good—thought I was actually endorsing Trump’s hiring of his family! Things have gone so far that, in my classes, I now feel compelled to issue a caveat: Just because a trait has evolved by natural selection does not mean that it is also morally desirable.