I loathe the Tories and since Charlie Brooker highlighted DC's resemblance to Iggle Piggle I take him even less seriously.
However, I do agree that families with two (or more!) productive, involved adults does have huge benefits in terms of an instant network of support - emotional, financial, child-rearing. You have someone to talk about your day with. Instantly bills are half as expensive per person. There's someone to help look after the children.
That is no criticism AT ALL of single parent families. People find themselves in that position for so many reasons - choice, abuse, affairs, death - and that is life. I was brought up in a single-parent family and though we were 'poor' I received an excellent education and have a successful career. Single parent families are just as capable of being successful as two parent families are of getting it all wrong.
But I suppose my point is I do get the central idea of two people working together to raise a family as being the ideal for the majority of people and therefore for wider society. Again, let me emphasise that the two people need to be productive and involved for it to be a benefit. If only one is productive whilst the other is a lazy sod who does nothing then of course I would argue that the productive one is better off alone.