Legal Question in Family Law in California

If you are not the biological father you cannot get joint custody, except in extremely rare circumstances in which you have held the child out to the world as your own and basically for all intents and purposes adopted the child, or if the child was born to your wife while you were married and living together, i.e., she cheated. If you are a step-father, you may get some visitation if the court finds it is in the child's best interests, but that is not custody.