A High Court judge has criticised the Government for focusing on gay marriage plans rather than the "crisis of family breakdown".
Here is a breakdown of the number of families by type:
- Of the UK's 18.2 million families, 12.2 million are married couples.
- Number of cohabiting couples has nearly doubled from 1.5 million in 1996 to 2.9 million in 2012.
- 7.6 million people live alone.
- Number of married people stayed constant at 21.2 million over a decade.
- Number of single adults rose by more than 3 million to 15.7 million.
- There were nearly 2 million lone parents with dependent children in the UK in 2012.
- 45% of 15- year-olds have experienced parental separation.
- Cohabiting couples are more than twice as likely as married couples to split by the time a child is 7.
Source: Marriage Foundation, Census