On April 8, 2014, President Obama signed the Non-Retaliation for Disclosure of Compensation Information into law. This executive order prohibits federal contractors from retaliating against workers who discuss their wages and salaries, but even if you don't work for the government, it's part of a trend that could affect your working life.
The Fifth Circuit has ruled in favor of a woman who was fired because she requested an appropriate place to pump at work. Her boss' actions have been found in violation of the employee's Title VII rights to be free from sex discrimination.
If you live in 49 of the 50 states, the answer to the above question is almost always, "Yes." Montana is the exception.