An apparatus may include an ultrasonic fingerprint sensor system and a control system. The control system may be configured for obtaining, via a scan of the fingerprint sensor system, current fingerprint image data from a surface of a target object, for extracting current fingerprint features from the current fingerprint image data and for determining whether the current fingerprint features match features of a previously-acquired fingerprint enrollment template. If there is a match, the control system may be configured for obtaining, via one or more additional scans of the fingerprint sensor system, current subsurface image data from a subsurface of the target object, for calculating an estimated biometric age of the target object, based at least in part on the current subsurface image data and for determining whether the estimated biometric age of the target object matches a previously-estimated biometric age.