The latest version of WhatsApp Beta adds an option to the Privacy menu for authentication via a saved fingerprint. Unfortunately, this function is not actually live yet; however, it clearly indicates that the messaging app's developers will make it available in a future version. Reports suggest that it will be compatible with Android devices with version 6.0 or later and working fingerprint sensors.
https://www.notebookcheck.net/WhatsApp-is-working-on-fingerprint-authentication-for-Android-devices.393221.0.html