Don't think I can add much to Dee's post except this little story:
I started my dive career in The Great White North (aka Canada), where I would typically be wearing about 2/3s of my body weight in gear: a full 1/4" neoprene drysuit with HP steel tank, 14# wt belt, plus 3# in ankle wts. (Probably something in the range of 80-100#.)
Basically, the diving philosophy in Canada is:
if you can't carry your own gear, you shouldn't be diving. Ergo, any female who was diving, was given her due. Unless proven otherwise, of course.
I became an Instructor in Dec '94, in 34F water, with 6" of snow on the ground & a balmy 28F air temp. I was the oldest one in my IDC of 8 people,
and the only woman at my IE of about 18. NO ONE treated me any differently than the other IDC/IE Candidates. And I never
expected it to be otherwise.
Since becoming an IDC Staff Instructor in '95, I have enjoyed working with a wide variety of students at various teaching levels (including Instructors). While it is true that the majority of them are still male, this IS changing. Like the time up in Tobermory where the Course Director looked around and his entire Leadership team was female: from Divemaster Candidates right up to his IDC Staff (me). He thought it was fantastic! And frankly, so did I.
I am happy to say that the people who have difficulty dealing with females in Dive Leadership roles seems to be decreasing. But there ARE still those around that have "problems" with us. And not all of them are students... some are fellow INSTRUCTORS.
All I can say is the best weapon against this is to always be professional. Then it is the misogamists who wind up looking like every bit the fools they are, and not US.
~SubMariner~