We human beings do have the natural ability, however, to make choices. We have been given the necessary natural equipment. We have a mind that can process information and understand the obligations imposed by the Law of God. We have a will that enables us to choose what we want to do. Prior to the Fall we also had a good intention, enabling us to choose the good. It is precisely this inclination to the good that was lost in the Fall. Original sin does not destroy our humanity or our ability to make choices. The natural ability or faculty remains intact. What was lost is the good intention or righteous desire for obedience. The unregenerate person is not inclined to obey God. He has no love for God that stirs his will to choose God.
From the book "What is Reformed Theology?: Understanding the Basics"