If you have full physical custody but joint legal custody can your ex have the child baptized without your permission?

That depends on whether it is stated in your parenting agreement as to who has the right to make religious decisions. Is it addressed? Is decision making joint? If this issue is not addressed then, yes, he/she can have the child baptised. My question to you would be...why does it really matter? If you thoroughly research baptism, you will find that it doesn't mean anything unless the party being baptised is consentual to it. A parent can have a child baptised with the intention of showing the world that they intend to raise that child in that particular religion, but actual baptism potrays the acknowledgement of Jesus Christ as Lord, and symbolizes the washing away of sins. Is your child old enough to consent and agree? If not, it is simply a ceremony for the sake of your ex. If your child is old enough, let him/her make their own decision about this. It just may be the most important decision they will ever make.

• Having "joint legal custody" means neither of you can do anything medical, religious, educational, etc. without the other's permission. The only way to do this without asking is if one has SOLE legal custody.