In order for there to be 'reverse' discrimination you would have to achieve complete parity across every possible subsection of society and then consciously discriminate against those who used to be in the minority. Affirmative action's purpose it to reverse discrimination, it unfortunately can't do too much about bias which is rampant in hiring decisions far and wide.

I'm a Canadian living in the US and I find it fascinating that a lot of people (esp. in software) are so very concerned that hiring be based on merit. That perspective completely leaves out an analysis that merit is something you can often only build on top of privilege. There's a great cartoon that I cannot find but which sums it up nicely. A white boy and a black boy come upon a high ledge and want to explore what's up there. So the white boy gets the black boy to give him a boost and climbs on top of him to reach the ledge. Then when the black boy reaches his hand up to ask for a lift getting up there himself the white boy says "You have to get up here on your own, I did".

It's too easy to say we make decisions "blind" or based on "merit" and that therefore removes the need for a deeper analysis of race, class and gender in our society. When we make decisions blind we might assume the pool being drawn from is fair to begin with and that those with merit naturally bubble up to the top but to really have a fair why not actually invite, engage, and draw in more people with a wider diversity so that you then know you will choose on real merit and not merit in a silo of white (and often male) privilege?