I assume that by referring to "joint residency" the Deputy is referring to joint custody of a child.
Section 11A of the Guardianship of Infants Act 1964 provides that, for the avoidance of doubt, it is declared that the court, in making an order under section 11 of the 1964 Act, may, if it thinks it appropriate, grant custody of a child to the child's father and mother jointly.
Section 11D, as inserted by the 1997 Act, provides that, in considering whether to make an order under section 11 and other sections, the court shall have regard to whether the child's best interests would be served by maintaining personal relations and direct contact with both his or her father and mother on a regular basis. Section 3 of the Guardianship of Infants Act provides that, where in any proceedings before any court the custody of a child is in question, the court shall have regard to the welfare of the child as the first and paramount consideration.
These legal provisions set out in simple form the underlying principles which should have effect in any decision in respect of a child, first, that joint custody is an option, second, that access to parents must have regard to the welfare of the child and, third, that it is the welfare of the child rather than the interests of the parents which should be the predominant consideration in the exercise of the Irish courts jurisdiction in respect of custody issues.