Joel et al.'s method systematically fails to detect large, consistent sex differences

In their widely publicized paper, Joel et al. (1) make two empirical claims about sex differences in features of the human brain: (i) “…internal consistency [in individuals’ sex-differentiated brain features] is rare” (p. 15472) and (ii) the amount of overlap in sex-differentiated features of male and female brains “undermines any attempt to distinguish between a ‘male’ and a ‘female’ form for specific brain features” (p. 15471). We argue that claim i is based on faulty methodology, and claim ii is misleading if extended to overall sex differences in brain structure. In regard to claim ii, Joel et al. (1) did not conduct analyses (e.g., discriminant analyses) designed to …