By politics.co.uk staff
Iain Duncan Smith will try to shift the debate away from gay marriage today as he argues in favour of "married relationships".
The launch of his department's social justice strategy comes soon after Cardinal Keith O'Brien, Britain's senior Catholic, attacked the coalition's plans to legalise gay marriage as "grotesque".
It is expected to set out statistics which make clear children do best when they are brought up in stable families.
"My concern is that in recent years government has been sending out the message that stable families don't matter," he is expected to say.
"We know that children raised by parents reporting high relationship quality and satisfaction tend to have higher levels of wellbeing, while intense conflict between parents has been shown to be detrimental to children's outcomes,"
"But when families break down, the consequences can be severe. That means we have to get behind families, not shrug our shoulders when they fall apart."
The coalition's family values agenda is gathering momentum at present. Earlier this month David Cameron announced a push to lower the barriers for adoption, arguing that care workers should not be picky when deciding which couples are suitable candidates.
"Given that married relationships tend to have greater longevity and stability than other forms, this government believes marriage often provides an excellent environment in which to bring up children," Mr Duncan Smith will add.
"So the government is clear that marriage should be supported and encouraged... at the heart of this, it means emphasising the government's support for marriage."
The institution of marriage appears to be enjoying something of a resurgence recently, having increased by 3.7% in 2010.