Scotland's most senior Roman Catholic has accused cabinet ministers in London and Edinburgh of devaluing family life.
Civil partnerships for gay couples provoked the wrath of Keith O'Brien
Cardinal Keith O'Brien criticised Westminster over civil partnerships and the Scottish Executive over changes to the laws on uncontested divorce.
He delivered his rebuke during his New Year's Day homily in St Mary's Cathedral in Edinburgh.
Critics have reacted angrily, accusing the cardinal of running the risk of inciting violence against gay people.
The church leader urged MSPs at Holyrood in particular to give "unequivocal support" for marriage.
He argued that alternative lifestyles were "undermining values which for generations have been treasured".
The cardinal claimed that the family remained "the basic social unit" to be recognised, protected and promoted as the most vital building block of society.
He told his congregation: "When our lawmakers condone and endorse trends in society which are ultimately ruinous of family life we are entitled to question their motivation and condemn their behaviour."
The cardinal's comments followed a call last week from Pope Benedict XVI to the UK Government to acknowledge "the indispensable role of stable marriage and family life" for the good of society.
But a Scottish Executive spokesman said the law had to reflect modern family life which included unmarried parents, co-habitation and divorce.
And the Catholic cardinal's remarks infuriated homosexual rights activists who called them "abusive."
Spokesman for the Gay and Lesbian Humanist Association, George Broadhead, said: "These relentless Vatican-inspired attacks are reaching a level that could lead to an escalation of violence against gay people.
Civil partnerships have not had the blessing of Scotland's top Catholic
"The Catholic Church's hierarchy has used increasingly extreme language in its desperate attempts to hold back progress for the gay community."
He added: "This kind of hate-mongering will be seen as a justification by some people for their already existing prejudices.
"It might even lead to more violence against a section of the community that is already subject to harassment and discrimination."
The first civil partnership ceremonies for gay couples took place days before Christmas in Scotland.
The Civil Partnership Act gives gay and lesbian couples the same legal rights as heterosexual couples.
But registrars in the Western Isles Council area have refused to offer ceremonies on moral grounds.
MSPs backed plans to speed up divorce after a fiercely-argued debate in December.
Where the split is not contested, the separation period will shorten from two years to one and from five years to two where one partner contests the case.