The 5h Amendment protects US citizens from providing self-incriminating testimony. That's an absolute (in theory). The question then becomes "what is testimon

The 5h Amendment protects US citizens from providing self-incriminating testimony. That's an absolute (in theory). The question then becomes "what is testimony?" Historically, the courts have ruled that physical things are NOT testimony. So, a court can demand you proceed a physical key to a safe. And now a fingerprint or facial scan. On the other side, courts have ruled combinations, passcodes, and passwords (things you know) are testimony and are protected by the 5th. I'm not sure of all courts have ruled the same way on fingerprints and facial scans, but if you consider them closer to a physical key than a secret code, then the current ruling makes sense. Personally, I'm have mixed feelings about it. I could be swayed either way with a solid argument. So far, I lean slightly towards biometrics are closer to physical keys, but only just barely.