I'm curious based on would-be standard samples such as
provided on Wikipedia; compare the same [male] speaker there trying to show the difference between (alveolo-palatal) ɕ and (palato-alveolar) ʃ.
provided on a Polish university page; of the three voices (one male, two female) trying to show the difference between ɕ (again) but retroflex non-palatalized ʂ (this time)... again I find the male voice (#2) making the least distinction between these.
So I'm curious if these are just my possibly biased observations based on a very limited sample and possibly my "untrained ears", or if there's something more general in this and males indeed have more trouble with alveolo-palatal pronunciation? Are there any surveys of speakers on these putative sex/gender differences with respect to ability to make a clear[er] pronunciation of alveolo-palatal?
Or if this is a bad tack, what are the physiological differences that make the "best", i.e. most clearly distinguishable alveolo-palatal sounds? (Something to do with lower lip or teeth, I might suspect.)