The board of directors of any school district, its employees or agents shall not discriminate in any way against any applicant for a certificated position or any certificated employee
(1) On account of his or her membership in any lawful organization, or
(2) For the orderly exercise during off-school hours of any rights guaranteed under the law to citizens generally, or
(3) For family relationship, except where covered by chapter 42.23
The school district personnel file on any certificated employee in the possession of the district, its employees, or agents shall not be withheld at any time from the inspection of that employee.