Catholic bishops in France and Spain warn that the promotion of same-sex marriage could threaten social peace.

“These long months of debate on the bill to allow marriage for persons of the same sex have highlighted predictable divisions,” said Cardinal Andre Vingt-Trois of Paris.

The cardinal said his country is witnessing “an organized and militant invasion by gender theory,” signaled by the rejection of “any difference between sexes as a means of human identification.”

The Spanish bishops say their 2005 same-sex marriage law remains “deeply unjust,” although the country’s Constitutional Court reaffirmed them in November.

More than 22,000 same-sex marriages have taken place under Spain’s 2005 same-sex law, Europe’s first to allow same-sex marriage and child adoption. Although the Constitutional Court rejected challenges to the law, the bishops have urged political parties to unite to overturn it.