Random numbers play an important role in digital security and are used in encryption, public key cryptography to ensure the safe and unchanged transmission. Random number generators are required to generate these random numbers, but true randomness is difficult to achieve and requires a true random source to generate the number which cannot be predicted from the knowledge of previous inputs. This paper discusses about incorporating biometrics and cryptography for stronger security and to generate random numbers with true randomness. Biometric systems are used to uniquely identify individuals in the security but uses a sophisticated procedure. Biometric signals are non-deterministic processes that are unpredictable and good source of randomness. This paper reviews the feasibility of using biometric signals in Random Number Generator (RNG) discuss whether biometric signals such as heartbeats, vascular patterns, iris scans and human Galvanic Skin Response (GSR) can be used in nearby future to generate reliable Random numbers. This paper will also review the work done towards generating random numbers using these biometric signals and the result of them, verified with statistical test suites such as NIST.