All the things you have seen have been present in every job I have worked here, including the men relaxing...or sleeping...on the job, with someone in a position of power assigning other workers' duties to the females to the point where they are not even taking their breaks. My husband has noted the same and more, and possibly has an even less favorable view of this state than I do. The good news is, you have a chance of winning a case on that alone, and the better news is you seem to have other complaints to back it up. Treating a worker differently than other workers based upon things like gender, race, etc. is discrimination. Recently, it became easier to both find out what your coworkers make and to file a complaint about unequal pay without retaliation. I would definitely try to find out if there is a noticeable gender gap in pay for the same experience/job levels. And as others have said, document everything, including specific comments that are made.
I would also go to another forum than this one to ask your question for several reasons!