A scientist aims at truth. A scientific discovery reveals the truth of nature. So, any discovery, useful or dangerous to mankind, must be made public. Every discovery can be put to both positive and negative use. It is left to the mankind to use it for the betterment of the people, society, to improve the quality of living or to use it for destruction. A discovery, which appears dangerous today, may become useful to mankind sometime later. In order to prevent misuse of scientific technology, we must build up public opinion against the misuse of a scientific discovery. Scientists should in fact take up two roles - to discover truth and to prevent its misuse.