Unnatural or deviant

An obvious - and oversimplified - example to illustrate this point might be sexual practice.

If heterosexual behaviour (sexual relationships between two people of a different biological sex) can be defined as a cultural universal (and, by extension, "natural" - because they appear in all known societies) then it is a small political step from this to see any other form of sexual relationship (such as homosexuality) as "unnatural" and deviant. This is not, of course, necessarily the case, but it does illustrate the point that we have to be careful - as individuals and sociologists - about how we present ideas and information.