Opponents of the multiregional theory reject it, in the first instance, on the grounds that it requires an improbable amount of parallel evolution by hominids throughout the Old World— in Africa, China, Europe, the most distant islands of Indonesia, wherever they appeared. Some also believe that multiregionalism encourages a racist view that anthropology took a very long time to rid itself of. In the early 1960s, a famous anthropologist named Carleton Coon of the University of Pennsylvania suggested that some modern races have different sources of origin, implying that some of us come from more superior stock than others. This hearkened back uncomfortably to earlier beliefs that some modern races such as the African "Bushmen" (properly the Kalahari San) and Australian Aborigines were more primitive than others.
Whatever Coon may personally have felt, the implication for many people was that some races are inherently more advanced, and that some humans could essentially constitute different species. The view, so instinctively offensive now, was widely popularized in many respectable places until fairly recent times. I have before me a popular book published by Time-Life Publications in 1961 called The Epic of Man based on a series of articles in Life magazine. In it you can find such comments as "Rhodesian man ... lived as recently as 25,000 years ago and may have been an ancestor of the African Negroes. His brain size was close to that of Homo sapiens." In other words black Africans were recently descended from creatures that were only "close" to Homo sapiens.