While the French government prepares to legalise homosexual marriage, Pope Benedict XVI spoke to around 30 bishops from western France, without mentioning the draft law but clearly referring to the debate around it.

During the feast of the Assumption on August 15th, France's Roman Catholic bishops invited their followers to say a prayer that was interpreted as a stand against homosexual marriage, sparking a row in France.

"Defending life and the family in society is not at all reactionary but rather prophetic because it comes back to promoting values which allow for the full blossoming of the human person, created in the image and resemblance of God," the pope said.

"We have there a true challenge to take on," he told the bishops at his summer home of Castel Gandolfo.

The family, "the foundation of social life," is threatened in many places, following a concept of human nature that has "proven defective," he said.

For the pope, "marriage and family are institutions which must be promoted and guaranteed …."

The working visits "ad limina" by the French bishops that will continue until December are the first to be made under the pontificate of Benedict XVI.