Can my 15 year old son choose to live with my ex without my permission?

First off the whole 12 year old thing depending on what state your in...doesn't matter. It is only a declaration for the GAL to read and decide where the child will live if it went to court. So the answer to your question is NO. The child should be returned to your custody and the easiest way to do that is file a contempt of court of the parenting plan. Unless there is immediate danger to the child living in your home, then they should be returned to you. They should file a modification at which time a GAL (Gaurdian Ad Litem) will help the courts decide who the child lives with...but like I tell a lot of people just because they want to doesn't mean they will change it. Teens change their minds like they change their underwear.

Yes

You have sole custody of your twelve year old,all you need to do is call the police and have them meet you at your ex's house all you need is to take with you your custody papers. Your child is not of the age that he can have a say in what parent he wants to live with the age is usally 15. The mother has no right to go against the stipulation of the court order giving you custody. You can file a motion against her for contempt of court. Even if the mother were to want the child to live with her she would have to file for custody and wait to see if the court would grant her the custody,and the court is not going to just take your son away from you,she would need to prove that you were an unfit father and that is hard to prove. You can go online to freequestions.com and ask an attorney any question and they will usally get back to you within 24 hours. There are different laws in different states but the one law that all states have in commom and that is once a parent is granted custody of their child that is where the child is to remain,the court is the only one that can change that. Don't let her pull this. You might want to sit your son down and see what his promblem is and make him aware that he needs to come to you and talk when there is a promblem so that you can work it out. Also parents asume that children have the right to decide what parent they want to live with. Wrong the law is at a certain age a child can have a say in where they want to live,the judge will listen to the child however the court will also listen to both parents before deciding on what they feel is in the best interest of the child. The child would need to be able to show the court a reason that would show the court that he is not being cared for by his father,if he has no just cause the court is noot going to just reverse the custody to the mom.

Everyone would have to back to court, and some kind of proof must be presented, courts don't just move kids at a kids whim.This usually takes awhile unless there's abuse. By then everyone gives up. Many times it the child support spouses are after. This is sad when children are used as pons. Manipulation can be a form of abuse, be careful.