You will not need a microscope to determine plant gender, as once flower parts start appearing it is quite simple to identify males from females.
I have posted pictures of both male and female primordia (pre-flowers) in week 7 in my diary "cannabis conundrums" if you are keen for an insight of what to look for. There are also pictures of hermaphrodite flowers and other strange cannabis growths too.
Hope this helps, Organoman.