Interesting topic, VGP.
First, I've always felt that "evil" doesn't really exist, in the same way "cold" or "darkness' don't exist. Evil is merely the absence of good. Not sure if that changes the discussion at all, but it's the root of how I feel on this topic...since the question, at least for me, becomes, "Are humans not inherently good?"
My answer probably gets a little convoluted...but the long story is that I feel everyone is born good, but can be warped by their environment. I honestly feel that if, say, someone like Hitler were to be raised in a family with much different ethical values regarding racism, he would have grown into a significantly different person. How a person is nurtured, what ethics are instilled on them by society, and what kind of people they connect with, I personally believe all of these play a much bigger role than anything genetic.
That being said, a lack of this nurturing means that someone won't be instilled with these values by default, and so someone raised in an environment lacking these values would be more likely to make choices based on what is most immediately convenient to them...which isn't necessarily "good". Looking at it that way, it does seem to poke a hole in my logic. I suppose it boils down to...are these baser motivations "good" or not...which I don't really have an answer to.
I feel like I didn't really answer the question...but it's interesting to type about!