Is this a pitbull?

[Bill Briscoe]

I'm not a dog expert, but it looks a lot like this:

http://en.wikipedia.org/wiki/Pit_bull

[Matt Devincenzo]

Originally posted by @Bill S.:

If none of the above work then you have the "man up" and tell them no pets. This may open you up for a illegal discrimination claim.

What would be the grounds for any sort of discrimination claim? Pets are not a protected class, neither are pet owners so I don't see how there would be any possibility to claim anything discriminatory.