the theory that the human race has descended from a single pair of individuals or a single ancestral type.
Origin of monogenism
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
The theory that all human beings are descended from a single pair of ancestors.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.