(a) For the purposes of this section, the following definitions apply:
(1) Biological sex. - As defined in G.S. 12-3.3.
(2) Immediate family member. - A parent, brother, sister, or grandparent. The term includes step and half relationships.
(3) Sleeping quarters. - A room with a bed that is intended to be used to house a person overnight or other area designated for overnight sleep.
(b) The governing body of a public school unit shall adopt a policy that prohibits students from sharing sleeping quarters with a member of the other biological sex during any activity or event authorized by a school within the public school unit, except when authorized by the school in either of the following circumstances:
(1) The parents or legal guardians of all students sharing the sleeping quarters have provided written permission to the school.
(2) The member of the other biological sex is the student's immediate family member.