Ideally, no. However, if parents share an email address and a student wishes to grant proxy access to both using that address, the student can do so.
If this is how the student wishes to set it up, we ask that, when completing the first-name field, the student enters both first names (example: Mary and David). In the relationship description field, enter “parents” or “mom and dad” so that it is clear to any administrator reviewing the permissions that this email address is for more than one person.