[Wallace T.]

Some creationists make mistakes. So do some evolutionists. There was an instance of school textbooks issued in the 1990s that claimed that the development of the human fetus reflected the course of evolution from single cell life upward through ever higher species until reaching primate and finally human status. This is a misconception based on early 20th Century speculation that was rejected by mainstream science in the 1960s. Yet this misconception was kept alive by reputable schoolbook publishers some 30 years after the theory was rejected.

Would it be valid to state that it is difficult to teach biology to evolutionists because of this error?

[VadeRetro]

Some creationists make mistakes. So do some evolutionists. There was an instance of school textbooks issued in the 1990s that claimed that the development of the human fetus reflected the course of evolution from single cell life upward through ever higher species until reaching primate and finally human status.

Embryological evidence is still considered in biology as a clue to evolutionary history. It's part of a growing area of study called evolutionary developmental biology ("evo-devo"). You seem to have spun all that out of existence. Good trick!