There is no federal law that protects workers from discrimination due to sexuality. In Washington state here, a gay group got this put on the ballot (many gays were really angry that they worked to put this to a vote because they knew it might lose and the ramifications would be much worse than if they had done nothing), and it did go down in the election. So now the right for employers to fire homosexuals was democratically reinforced, and the legislature went ahead and nullified any single sex marriages made in Hawaii or elsewhere. We have a ways to go. But so many strides have been made in gay rights that I have to expect that the majority might finally support at least these minimal levels of rights 20 years from now.
Statistics on employment and earnings levels by homosexuals are inherently unreliable. You'd have to expect that perhaps half of gays are not out or completely open, and the most 'out' individuals would usually tend to be the most highly educated and wealthy.
CP