Are people born with prejudices or is it something learned

I don't believe that people can be born with prejudices. It's just not possible. I think it's something learned. Why? Because the environments and people a person is exposed to when he/she is young shapes the way that person thinks.
Ways of thinking (including prejudices) are not biologically hereditary, therefore you cannot be born with them. If ways of thinking were hereditary and you can be born with ways of thinking, then wouldn't children always be in agreement with their parents?
Anyway, therefore, prejudices are always something learned, based on who a person learns from, and what environments that person is around.