I live in the state of California and 13 years ago I had a baby and had unknown for the fathers name until I decided to get married. Although the man I married wasn't the biological father I called and got his name added where the father's name goes. I was married to him for 5 years and divorced him and remarried later to my child's biological father. I've been married now for 7 years and my ex-husband still has visitation rights to my child and she has his last name. My child is not happy with him and I've tried going to court to get full custody. Is there a way after all of this time my husband, my child's biological father can do a paternity test and we can get full custody of her? My ex is not a nice person and seems to charm his way through the court system.

Let me see you committed fraud by lying to the courts as to the true father was and had him added to the birth certificate?

I guess you could go confess all of this to the judge and if he does not put you and your ex in jail for all of this, they may straighten it out.
But in general I think any time frame to challenge has long past.
But the real bio father can try, he will have to hire an attorney and this will get real dirty and nasty before it is all over.

But yes, a man who would take responsibility of a child he knew was not his, and still want contact with her, yes courts are going to look on him with better view point.

By law the child is your ex husbands.

You would have to go to court and request a paternity test... of which YOU will have to pay for.

California has two years statute of limitation for changing paternity. In your case no one can dispute your ex-husband's paternity.