As iNow says, we are all ruled by chemistry. So, the discussion does indeed depend on how you define the terms. Traditionally free will has been regarded as the ability of an individual to make its own decisions using its own brain. This is still the case. Our decisions may be driven by internal factors rather than rational thought-- but ultimately, our decisions come from within us. And, since our neural connections are driven by our experiences in addition to genetics, we are all to some degree unique. Thus, I would argue we have free will. However, not all would agree with me.