The Vatican says the traditional family faces its biggest threat in history from such practices as homosexual marriage, abortion, and contraception.
In a new report, the Vatican's Pontifical Council for the Family called abortion an "abominable crime" and said it was "inconceivable" that it goes unpunished in many countries.
It also calls gay marriage and civil unions threats to a natural institution.
Same sex marriage is legal in Belgium, Canada, the Netherlands, and Spain.
President Bush has called for a constitutional ban on gay marriage in the United States. But congressional observers say there is little chance of getting it passed in Congress.
Some information for this report was provided by AP and Reuters.