It is not the case, as Martin Crewe, director of Barnardo's Scotland, suggests, that "children's development does not appear to be affected by parents marital status" ("Barnardo's chief joins gay marriage row", The Herald, June 19 and Letters, June 19).

Studies strongly suggest otherwise, with parents being four times more likely to split up after five years if they are not married.

Love and care are the critical factors in bringing up children but, without definition, these words are a meaningless truism, making one feel good but without any substantive content.

Children need the commitment of two parents who love one another and express that commitment in the stable relationship of marriage. To argue otherwise is to fly in the face of the evidence.

David Robertson,

Solas CPC, St Peters Free Church,

4 St Peter Street, Dundee.

It is disappointing to see Barnardo's join the bandwagon in favour of redefining marriage.

The evidence is abundant that children with their biological parents committed in marriage give the best chances for children. Surely we should promote that rather than undermine it?

Yet Martin Crewe creates his own private list of criteria for good parenting, insisting that the fundamental factor that a mum be a woman and a dad a man holds no significance for children. This is an organisation which is supposed to put children at the heart of its concerns, not political correctness.

John Deighan,

Parliamentary Officer,

Catholic Parliamentary Office,

5 St Vincent Place, Glasgow.