Fam. Code, § 3103

(a) Notwithstanding any other provision of law, in a proceeding described in Section 3021, the court may grant reasonable visitation to a grandparent of a minor child of a party to the proceeding if the court determines that visitation by the grandparent is in the best interest of the child.

(b) If a protective order as defined in Section 6218 has been directed to the grandparent during the pendency of the proceeding, the court shall consider whether the best interest of the child requires that visitation by the grandparent be denied.

(c) The petitioner shall give notice of the petition to each of the parents of the child, any stepparent, and any person who has physical custody of the child, by certified mail, return receipt requested, postage prepaid, to the person’s last known address, or to the attorneys of record of the parties to the proceeding.

(d) There is a rebuttable presumption affecting the burden of proof that the visitation of a grandparent is not in the best interest of a minor child if the child’s parents agree that the grandparent should not be granted visitation rights.

(e) Visitation rights may not be ordered under this section if that would conflict with a right of custody or visitation of a birth parent who is not a party to the proceeding.

(f) Visitation ordered pursuant to this section shall not create a basis for or against a change of residence of the child, but shall be one of the factors for the court to consider in ordering a change of residence.

(g) When a court orders grandparental visitation pursuant to this section, the court in its discretion may, based upon the relevant circumstances of the case:

(1) Allocate the percentage of grandparental visitation between the parents for purposes of the calculation of child support pursuant to the statewide uniform guideline (Article 2 (commencing with Section 4050) of Chapter 2 of Part 2 of Division 9).

(2) Notwithstanding Sections 3930 and 3951, order a parent or grandparent to pay to the other, an amount for the support of the child or grandchild. For purposes of this paragraph, “support” means costs related to visitation such as any of the following:

(A) Transportation.

(B) Provision of basic expenses for the child or grandchild, such as medical expenses, day care costs, and other necessities.

(h) As used in this section, “birth parent” means “birth parent” as defined in Section 8512.