Parental leave would probably require—and I don't want to speak on behalf of the Law Clerk—modifications to the Parliament of Canada Act where attendance is regulated by section 57. The attendance regulations include illness as a reason for being absent during a sitting day, but they don't necessarily include the reason of giving birth to a child, parental leave, or even taking care of a sick child. These provisions are included in the Parliament of Canada Act, and my pay service is administering these provisions for you as members. These, of course, would require higher change to the legislation.
On April 14th, 2016. See this statement in context.