Are Emotions Just Human?

I just got done watching Blade Runner. I really wish they had stuck more with the novel, but there were some interesting additions to the story. Ironically, I think the film concentrated mostly on the pure technology and fighting instead of the actual moral issue regarding the androids.
What really struck me was the fact that they said flat out in the film that they believed there was a chance that the androids would develop their own emotional responses. In both the film and the novel you can see that the androids do experience some sort of emotion, especially when Rachel and Pris (in the novel) discover that they aren't human. They do express a frustration and a sense of loss when they realize that their memories aren't actually their own. There is an attachment to the other androids and even a few humans that they meet. I think these interactions do raise an interesting point about wether or not emotions are only in the realm of humans.