Prohibit multiple accounts with identical email and identical students

I just had a parent sign up for an account with the same email for which I had previously set up an account, and registering the same student with identical birthdate. This should not be allowed. Instead, a prompt should be displayed informing the parent that the email account already exists and click Continue to use that account.

ADDED 1/17/22: I am also having parents sign up the same child with the same DOB. This has happened more than once. IF by some chance a parent would actually want to set up the same child with a second account (I have no idea why), at least there should be a prompt presented to the admin creating the dup account that an account already exists and the parent/student name must be edited so it is unique.