In a response to the Prime Minister's announcement of the equal marriage bill yesterday, the Church of England said its defence of the traditional understanding of marriage was "not knee-jerk resistance to change".
Rather, the Church said it was defending the traditional definition of marriage out of a "conviction that the consequences of change will not be beneficial for society as a whole".
"Our concern is for the way the meaning of marriage will change for everyone, gay or straight, if the proposals are enacted," the statement said.
"Because we believe that the inherited understanding of marriage contributes a vast amount to the common good, our defence of that understanding is motivated by a concern for the good of all in society."
The Church defended the "uniqueness" of marriage, saying that it embodied the distinctiveness of men and women seen most explicitly in their union's potential for procreation.
It warned that changing the nature of marriage forever would be "divisive and deliver no obvious legal gains given the rights already conferred by civil partnerships".
"We believe that redefining marriage to include same-sex relationships will entail a dilution in the meaning of marriage for everyone by excluding the fundamental complementarity of men and women from the social and legal definition of marriage," the Church said.
The Church also expressed concern that there was no democratic mandate for the legalisation of marriage as it had not been referred to in the Queen's speech or in any party manifesto.
"In our view the Government will require an overwhelming mandate from the consultation to move forward with on these proposals and to make them a legislative priority," it said.
The equal marriage bill is to be introduced to Parliament next week. David Cameron said the bill would allow same-sex marriage ceremonies to be performed in churches.
He insisted that churches would not be forced to perform the ceremonies.
However, his assurances were dismissed by the Christian Legal Centre, which warned that equality legislation will not provide any effective protection for churches from litigation.
"Any such assurances are meaningless," said CLC director Andrea Minichiello Williams.
"At the Christian Legal Centre we have seen countless cases where Christians have been forced out of their jobs for their refusal to condone and promote homosexual practice.
"Their views have not been respected or accommodated and Mr Cameron has ignored their plight.
"This does not bode well for British Christians if further legislation is passed. Assurances to churches who do not wish to perform same-sex 'marriages' fly in the face of all the evidence."