This has happened suddenly. I'm being referred to as a girl though my character is a guy. Happened out of the blue. Thought at first they were talking to Veronica my companion but nope, was just told, "Cheer up lady," by an Atomic Wrangler guard. Very ANNOYING. What happened and how do I fix it?

Only that NPC? Or lots more? If you're on consoles, I don't think there's anything you can do, if you're on PC, I don't think there's something you can do either, maybe you could search some console commands. This is game is full of bugs. Starting a new game would be an option. But remember, maybe that was just a screwed up NPC. Benny had some weird ass but characteristic dialogue lines too.

Maybe that npc was making fun of you by calling you a lady lol

So you dismissed Veronica and they still called you lady?

Lol. Sorry, not helpful but it was funny =)