Yes, by the parent
No. If you have your parent's permission, then you can live with who you want.
Not without parent permission. It could be considered kidnapping without that.
18 without parent permission
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No, they can't.
A 12 year old is not allowed to volunteer without their parents permission in Reno, Nevada. If they get their parents permission, they can volunteer almost anywhere.
No the custodial parent has to have either the courts permission or the non-custodians permission.
No, you will need the other parents and the courts permission.
You can't get married at 14 with your parents permission in any civilised country never mind without their permission.
You have to be 18.