Conservative leader David Cameron has strongly defended marriage in a speech to the party's Welsh spring conference in Cardiff.
Fathers who run away from their family responsibilities should feel "the full force of shame", Mr Cameron said.
He warned that family breakdown is the central factor in social breakdown in Britain.
Closing the conference , Mr Cameron warned 70% of young offenders are from lone-parent families.
He said he did not care if some people said singling out marriage in this way was wrong.
Mr Cameron said he was not suggesting single parents do a bad job, just that "kids do best when mum and dad are both there for them".
In a speech focusing on "social responsibility"; he told party activists that while the Conservatives had "won the economic argument" their priority should now be "combating social breakdown".
He insisted the Conservatives must be the party of the family and should not ignore the fact that "one in two co-habiting parents split up before their child's fifth birthday, compared to one in twelve married parents. That is why we support marriage"
Mr Cameron also told party members in Wales that they have 60 days to spread the message of his new brand of Conservatism, in order to return "a large team" of members to the Welsh assembly.
The Tory leader said the party was on its "way back into government" and insisted that the effort "could start here in Wales".
On Saturday assembly Conservative leader Nick Bourne has said the party will give every household £20 of low energy light bulbs if they win power in May's poll.
Mr Bourne told the party's conference in Cardiff that climate change is the biggest challenge of our age.
He said the policy would cost £6m a year and make a "very real difference to climate change in our country."
Labour spin had damaged UK politics, Mr Hague said
He said people must try to buy locally, cut supermarket packaging and develop renewable energy technologies
In a wide-ranging speech setting out the main issues which will form the core of the Welsh Conservative assembly election manifesto, Mr Bourne said health was the party's other key policy to campaign on.
He promised to end Labour's hospital shake-up and "consult on the best way forward to restore trust in our communities".
Shadow foreign secretary William Hague also told delegates that the Conservatives would table a commons motion for an inquiry into the Iraq war if the government failed to do so.
He promised a Conservative government would end the "sofa-style decision making" of Tony Blair's Downing Street.
The shadow foreign secretary said Mr Blair's method of government led to "weak and last minute decision making".
He also made a blistering attack on Labour spin which he said had done huge damage to British politics.