If I knew a lawyer, I'd sue Dr. Sanjay Gupta for anthropological malpractice. On his CNN program "House Call" this morning, Dr. Gupta had a segment on skin cancer. To discuss the particular problems this poses for people with dark skin color, Dr. Gupta brought on a "specialist in ethnic skin."
We might expect first-year college students to have such a muddled notion of "ethnicity," but a presumably well-educated person like Dr. Gupta? Uncritically applying the prevailing folk model concept of "ethnicity," Dr. Gupta has conflated ethnicity with biological differences, such as skin color. Anthropologists, in constructing scientific descriptions and explanations, take care to separate ethnicity from biology. Ethnicity, for anthropologists, refers to shared cultural features such as language, religion, food preferences, and so on: features that are not specified in the genome, but rather handed down in the process of enculturation. To conflate ethnicity, i.e. culture, with biology is to risk repeating the essentialism that supported Social Darwinism, the genocide of Native Americans, the eugenics movement, the Nazi Holocaust...
Franz Boas demonstrated that culture, "race" (by which he meant strictly biological difference), and language are independent variables in his book Race, Language, and Culture, published in... 1940! Boas used ethnographic case studies to show that biologically similar groups of people can have very different languages or cultures, biologically different groups can have similar languages and cultures, and so on, in any combination. A classic modern example of this involves the Warlpiri people of central Australia, who speak a language with noun declensions using suffixes, like Latin, despite being about as biologically distant from the Romans as possible.
Here's another example: a group of schoolchildren I photographed in Pinar Del Río, Cuba, back in 2002. What ethnic group do they all belong to? My guess: Cuban. Which ones have "ethnic skin?" My guess: none, since there is no such thing.
This is why an introduction to general anthropology should be required for every person on the planet.