Your question is ill-formed, and cannot be answered without further information. In particular, you haven't specified the domain of inquiry. If you're asking

Your question is ill-formed, and cannot be answered without further information. In particular, you haven't specified the domain of inquiry. If you're asking about the probability that a person reading your question is human, the answer is close to 1. If, on the other hand, you're asking about the probability that a group of protons, neutrons, and electrons form themselves into a human, it is vanishingly small.