From a May 14, 2021 article in The College Fix:

John Staddon, an emeritus professor of psychology and neuroscience at Duke University, was taken off the Society for Behavioral Neuroscience and Comparative Psychology Division 6 listserv overseen by the APA.

. . .

The topic that appears to have gotten him removed was the suggestion that there are only two sexes. According to Staddon, what likely got him taken off was this post: “Hmm… Binary view of sex false? What is the evidence? Is there a Z chromosome?”