Vatican City, October 27 - Pope Francis on Thursday spoke out against a recent "tendency to cancel out" the differences between men and woman. This difference, he said at an audience with the John Paul II Institute for the Family, was a "richness" and part of "God's design". He said God had "entrusted the alliance of man and woman to the world and history". It is "very disconcerting," Francis went on, "to see that now this culture appears to be blocked by a tendency to cancel the difference instead of solving the problems that mortify it". The pope added that marriage was being threatened by "narcissism and selfishness".