A ban on conversion therapy does not take away parental rights any more than the law does by not allowing parents to beat or abuse their children.  Children will not benefit from therapy that is ineffective.  Taking away CT does not mean limiting access to professional help for children.  If CT were really effective, then it should work when a child turns 18 and chooses to undergo it.  Homosexuality was removed from the DSM as a mental illness for a reason.