You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Race_(human_categorization)

Context:
In the early 20th century, many anthropologists accepted and taught the belief that biologically distinct races were isomorphic with distinct linguistic, cultural, and social groups, while popularly applying that belief to the field of eugenics, in conjunction with a practice that is now called scientific racism. After the Nazi eugenics program, racial essentialism lost widespread popularity. Race anthropologists were pressured to acknowledge findings coming from studies of culture and population genetics, and to revise their conclusions about the sources of phenotypic variation. A significant number of modern anthropologists and biologists in the West came to view race as an invalid genetic or biological designation.

Question:
What effect did the Nazi eugenics program have on racial essentialism? 

lost widespread popularity