GENEVA • In 2008, school officials in Basel, Switzerland, ordered a Muslim couple to enrol their daughters in a mandatory swimming class, despite the parents' objections to having their girls learn alongside boys.

The officials offered some accommodations: The girls, aged nine and seven then, could wear body-covering swimsuits, known as burkinis, and they could undress for the class without any boys present.

But the parents refused and, in 2010, officials imposed a fine of 1,400 Swiss francs (S$2,000).

The parents, Mr Aziz Osmanoglu and Ms Sehabat Kocabas, who have Swiss and Turkish nationality, sued. The European Court of Human Rights on Tuesday upheld the Swiss officials' decision, rejecting the parents' argument that the authorities had violated the "freedom of thought, conscience and religion" guaranteed by the European Convention on Human Rights, which the court enforces.

"The public interest in following the full school curriculum should prevail over the applicants' private interest in obtaining an exemption from mixed swimming lessons for their daughters," the court found.

The authorities ruled that lessons mixing boys and girls were an important part of the school curriculum; they did allow that the girls could apply for an exemption on religious grounds, but only if they had gone through puberty, which was not the case for the girls.

The parents argued that although the Quran does not require girls' bodies to be covered until puberty, "their belief commanded them to prepare their daughters for the precepts that would be applied to them from puberty" onwards, according to the court's summary of the case.

The decision, by a chamber of seven judges, did not dispute that the denial of the parents' request interfered with their religious freedom, but it emphasised that the need for social cohesion and integration trumped the family's wishes.

The court said schools play "a special role in... social integration, particularly where children of foreign origin were concerned", and, as such, ensuring the girls' "successful social integration according to local customs and mores" took precedence over religious concerns.

The parents have three months to appeal against the court's decision.

The case comes amid an acrimonious debate in Europe over the place of Islam in public life that has been fuelled by an unprecedented migrant influx largely from the Middle East, and the radicalisation of marginalised Muslim youths, thousands of whom have been drawn to extremist groups such as the Islamic State in Iraq and Syria.

NYTIMES, AGENCE FRANCE-PRESSE