Situation:
If the Birthday not known for the Patient, so can only the Patient age be entered.
Settings:
open the Settings Page System\Database\Database and set the following Setting (4.6 or 5.x)
Workflow:
(1) available "New Patient" (2) Input from Patient First and Last Name (3) Input "Age" => the "Date of birth" is allways Default by 01. 01.