I don't reckon you're born with anything.
If your parents / whatever long-term role models are generous, you probably will be too.
I'm not saying you come out a carbon copy of them, but a lot of the time kids inherit certain characteristics from their parents. Like any trait, it is learned.
If you mean later on in life, well, I like to think that anybody can change, but whether or not they will is a different matter entirely.
If trees could scream, would we be so quick to chop them down? We might, if they screamed all the time for no good reason.