No need to do this manually! Providing that you have a spreadsheet/data source that has all students and a parent/guardian column - so that you can create relationship during import. I'll try dig up a field mapping for you - and post it here shortly.
EDIT: found a wiki page for you: https://wiki.civicrm.org/confluence/display/CRMDOC/Importing+Student,+Staff+and+Parents
PS - though tailored for CiviSchool - which is no longer supported - the import/mapping screens will show you how what import/mapping to use.
EDIT: highlighting the key screens from this Wiki - it's a two pass import:
First: import the student:
Next: import the parent: key is Child of relationship to the Student: