I can only comment from a UK legal perspective, but it would seem that if a parent has parental responsibility for a child this means that they can make decisions on behalf of the child without the other partners consent; the only way to prevent this would be take legal action under Section 8 Children Act 1989.
This means first of all obtaining a court order preventing the other parent from taking actions which would not be in the best interests of the child; admittedly this is extremely difficult on the basis that religious freedoms and human rights issues are at stake. The childs best interests will be paramount in these cases but they will tread very carefully in order to avoid offending the right to religious freedoms.
In Palou - Martinez v France [2004] 2 FLR 810it was held that it is wrong to make such orders on the basis of religion only; any successful case will need to concentrate on actual actions which undermine the family unit, this isn't tolerated in any respect by the courts. The Claimant in this case failed to properly concentrate on these issues hence the reason why the court fell into error. Click on the link to see the facts and the judgement.
Tricky area but not impossible.
(Gary) DB74