Gender, unfortunately is often overlooked in legislation that is aimed at discriminatory practices. In fact, you might be surprised to learn that gender is not even protected by the Constitution. The Equal Rights Amendment, which was proposed in the 70s, would have given women absolute equality under the Constitution, but it was never ratified. Of course, the Civil Rights Act prohibits gender based discrimination. But there is nothing that would prevent a future Supreme Court from finding the Act unconstitutional.
I have recently begun to question ALL hate crime legislation, though. I think it violates the 14th amendment's equal protection clause. If I am assaulted because someone doesn't like the way I look or what I say, I am treated differently (i.e., given a different level of protection) than someone who is assaulted because they are a member of a protected class.