“Evil” has never been proven to be genetic. You can perhaps ask if some people are born more aggressive (that is – with a higher level of testosterone) than usual. But from biological perspective, it wouldn’t be wise of nature to let us bear off-spring that hurts the species.
If we talk about mental defects then some people are born mentally handicapped, yes. But can insane truly be defined as evil?
It's like asking:
Are some people born good?
Omega> So do you think that Good and Evil are genetic? To me, it's not in the skin, brain, or any actual part of a body. I think that it's in the soul. I think that you are either born good or evil and for the most part people are born good and they just don't turn evil or evil to good. You are born good or evil and it comes to play as an adult. I really have never heard of an evil kid.