Laws like this are what drives the practice underground.
It will still be done, the people who want it done on religious grounds will claim that they are being persecuted and that their fundamental rights and freedoms are being violated, and will just do it in secret, or the families will take their children out of the jurisdiction to somewhere that it is permitted.
Once it's done, it can't be undone.
The World Health Organization ban on female circumcision has the same problems. Parents who want it done, will find someone to do it. The communities who want it done have networks that direct the families to practitioners, or they will take a "vacation" home and the girls come back with their lady-parts mutilated and sewn up.
My fear is that outlawing the practice and driving religiously motivated people to find ways to circumvent the law will result in children being taken to unsanitary back-alley butchers, that will make matters worse in terms of potential for infection, visits to emergency rooms for excessive bleeding, and kidney damage when these kids are so swollen that they can't pee, not to mention that some parents will avoid going to doctors when there are problems post-procedure, because they are terrified that they will be reported to authorities.