With so many people crossing borders every day, how do we know we're not letting dangerous people into our countries? One response is biometric identification technology. It has been developed to recognize individuals and to identify criminals. In fact, biometric identification is not a new invention. Law enforcement agencies have been using photographs and fingerprints as biometric identifiers since the late 19th century. Today, biometric identification technology, including both physiological and behavioral biometrics, has become increasingly prevalent as a means of enhancing security and protecting individuals' interests. Physiological biometrics, such as fingerprints and facial features, use human morphology to identify or recognize individuals. Besides fingerprint scanners, there are software programs that identify faces, palms, and irises. Scanning these physical features ensures that the person being scanned is who he or she claims to be. Unlike personal identification numbers, which are used to access bank accounts, biometric identifiers are extremely difficult, if not impossible, for criminals to steal. Behavioral biometrics can also be used to identify people. Certain behaviors are unique to individuals, such as their speech or the way they type. The classic behavioral biometric marker is a person's signature, but it can be problematic as it can be copied. However, people do automatically recognize subtleties in the way a person speaks, such as intonation and regional accents. Typing patterns, likewise, would be very difficult to observe and mimic convincingly. Biometrics can have two potential applications: identification and identity verification. Identification uses biometric information to discover the identity of an unknown person. DNA evidence has joined fingerprints as a common tool of law enforcement for this purpose. Today, we use passports to verify our identity when crossing borders, but passports can be stolen or forged. An effective biometric identification system would be difficult to fool. Because of this, many countries are considering biometric additions to or replacements of existing identification system. India, for instance, has already implemented such a system, which utilizes fingerprint and iris scans, in addition to photographs. While biometric identification technology shows promise in various applications, there are ethical concerns surrounding the development of biometric identification technology. Critics worry about the possibility of criminal uses of the technology, as legitimate organizations can use biometric scanners to verify personal information. And civil liberties advocates are concerned about the potential for abuse by authorities. Therefore, policymakers will need to balance security and law enforcement against personal freedom and privacy. Ethical considerations must be taken into account when developing biometric identification technology.