Q. How do courts decide whether to award joint or sole custody?
Family Code section 3010 provides that a mother and a father "are equally entitled to the custody of the child."
However, Family Code section 3020 sets forth the California legislative declaration that the chief concern of the State in with regard to custody issues is the "best interests" of the minor children. Lawyer's and judges refer to this as the "BIC" (best interests of child) standard. As a matter of public policy, BIC always trumps parental rights and interests; of course, BIC is a moving target. Family Code section 3011 sets forth a non-exhaustive list of factors that bear upon the BIC.
Section 3020 is an extremely important statute nonetheless, because it also expresses California public policy to (a) "assure the health, safety, and welfare of children" and (b) to "assure that children have frequent and continuing contact with both parents after the parents have separated or dissolved their marriage, or ended their relationship, and to encourage parents to share the rights and responsibilities of child rearing in order to effect this policy, except where the contact would not be in best interest of the child, as provided in Section 3011."
Here it is important to comment that when a court makes a custody determination, it is required "upon the request of either party," to issue a statement of the decision explaining the factual and legal basis for its findings. Family Code section 3022.3.
So, the court must make a decision, when parents cannot agree, based upon the evidence of what is in the child's best interest. Along these lines, there are certain presumptions that also apply which will affect the outcome of the BIC determination. Examples include a history of domestic violence by either party (Family Code section 3044) or habitual drug or alcohol abuse (FC section 3011(d)). In those situations the Court must actually state why it granted joint custody to a parent who is guilty of abuse, or is a continuing substance abuser, and those reasons may be hard to find.