Authentication is the primary requirement for any system by means of privacy & security. Physiological biometrics is based on direct measurements of a part of the human body, such as finger-scan, facial scan, iris-scan, hand-scan, and retina-scan. Behavioral biometrics is based on measurements and data derived from an action and therefore indirectly measure characteristics of the human body, such as voice-scan and signature-scan. The element of time is essential to behavioral biometrics because it may change with time. In this paper the discussion is made on various aspects for designing a biometric recognition system for human authentication and related topics to the particular feature of biometric parameter.