The Inherit rollout limits which transforms a child inherits. It constrains the links between a selected object and its parent for any axis of position, rotation, or scale.
Hierarchy panel > Link Info button > Inherit rolloutTo prevent inheritance of X rotation in a hierarchy:
Select an object, then turn off X in the Rotate group on the Inherit rollout.
Turn off any axis in the Move, Rotate, or Scale groups to prevent inheritance.
When you turn on an axis, transform information passes from the parent to the child for that axis. When you turn off an axis, transform information on that axis is ignored by the child.