Depends on how you define 'evil'... fact is, place several babies... say about 10 to 15 months old... old enough to sit up and be fully aware of others. It won't take long before one or more becomes the dominant child and forces their will (in a baby fashion) on others. We've all seen them forcefully strike another child... I'm sure one can say they don't have any concept of the possible results of their actions, but the action, seen from an adult persepective, has a tint of evil, no?
Seems to me upbringing has to affect at this point and the action(s) are inherent...