I know that you've installed the update from
my other post, so you should be able to view the gender that the customer has selected (without this update it would always default to female no matter what was actually selected).
With or without this update, you cannot change any of the customers’ information from the admin panel. Repeat- my update did not break that function; it doesn't work even in the default v1.1.0. And it's not just the gender; you can't change any of the information. But honestly, why would you need to? The customer can change any of there info from the normal, non-admin account details page, so you shouldn't have to do it for them (with or without there knowledge).
The only exception to this is the "Discount”; which you would need to change from the admin panel, but you can’t. If you really, really needed to; you could change the info directly in the database.