Need Help: Gay and Lesbian Hiring Discrimination Law

[HFishbine]

I'm working on a campaign for a city council candidate who would like to work to eliminate hiring discrimination in the city based on sexuality. (And he's a republican!)

The city's current anti-discrimination ordinance does not address discrimination based on sexual preference. Since the ultimate course of action for the commission that investigates descrimination complaints is to refer those that cannot be resolved to a civil court, does anybody know where federal law stands on this issue? (Yes, I know that state law would be considered first, and I'm looking into that, but I'm looking here for the highest legal authority to have issued an opinion.)

Links to cases or authoritative sources would be much appreciated. Thanks!

edit: spelling (some of it, anyway.)