From Reuters.com:
Gay marriage a threat to humanity's future: Pope | Reuters
In other words, Pope Benedict is desperate because same-sex relationships and families are becoming more accepted. Such acceptance is based on people becoming more familiar with gay individuals through personal experience, the media and studies that disprove myths about them. Because those myths are easily disproved with tangible evidence, Benedict has realized that he must try to scare people into agreeing with him by appealing to more vague and subjective concepts like "dignity" and "promotion of family" and "social cohesion".
Frankly, Benedict is moving the church backwards as this ridiculousness undermines its increased embracing of scientific inquiry in modern history by basing arguments about measurable realities, like the effect of same-sex parenting on children, on nonsense rather than research. By making these comments, he's likely just going to alienate more Catholics, thereby continuing to make the Church its own worst enemy. One would think that after its child sex abuse scandal, it would take a dose of humility. Guess not.