Family breakdowns lie at the heart of many of Britain's most pressing problems, a Conservative Party report on social justice is expected to say.
Drafted by a policy group led by Iain Duncan Smith, it will warn about a growing underclass.
Tory leader David Cameron welcomed the report on tackling poverty, describing it as "powerful and convincing".
Mr Duncan Smith warns of an "increasingly dysfunctional society" which breeds criminality.
BBC political correspondent Teri Stiastny said it "paints a gloomy picture of a society where for some family breakdown, drug and alcohol abuse, debt and failure in education combine".
One of the main problems identified by Mr Duncan Smith is a growing number of co-habiting couples who split up while their children are young.
The policy review group's report does not set out policy plans but recommendations on how to tackle the problems are expected in a few months' time.
Mr Duncan Smith believes that marriage had been "undermined" by the tax and benefits system under Labour.
In response to the report's findings, Mr Cameron said families are the "ultimate source of our society's strength or weakness".
He said his party must "look at ways of supporting families and also supporting marriage so that couples are encouraged to get together and stay together".
Mr Cameron said the report "demonstrates clearly the links that exist between social breakdown, family breakdown, educational failure, indebtedness and drug and alcohol abuse".
He added: "Families matter because almost every social problem that we face comes down to family stability."
Mr Cameron repeated his party conference speech pledge to test every Conservative policy on whether it helps families.
But for Labour, the Work and Pensions secretary John Hutton said it sounded like the Conservatives were going "back to basics again" and talking about Victorian values.
He said it was "nonsense" to suggest that tweaking the tax system could lead to families staying together, saying that had been tried in past decades which saw divorce rates "go through the roof".