The incoming leader of the Church of England has been criticised for "endorsing immorality" after it emerged a gay priest in his own diocese fostered a 15-year-old boy.

Dr Rowan Williams met the priest at the weekend and accepted his undertaking not to conduct services.

But Church traditionalists opposed to homosexuality have been angered by the news, arguing children should be raised in heterosexual, two-parent families.

The Bible tells us same-sex relationships are always sinful and wrong - we cannot have our leaders endorsing immorality - [Dr Williams] must be disciplined

George Curry, Church Society

Currently Archbishop of Wales, Dr Williams - who refuses to stigmatise lesbian and gay clergy - will shortly leave the Monmouth diocese to become Archbishop of Canterbury.

This is the latest time his views - which have been criticised by some groups within the Church as as too liberal - have been spotlighted.

The teenager in foster care has suffered severe learning difficulties and behavioural problems.

He is being cared for by the priest and his long-term partner, who cannot be identified for legal reasons.

Both men have been known and helpful to the child - when his mother could not cope - for over ten years.

The priest met Dr Williams on Saturday when his offer to surrender his permission to conduct services was accepted.

'Endorsing immorality'

But conservative evangelical group Reform has said Dr Williams is "validating" the gay movement in defiance of Church policy.

"Social services have been irresponsible," said Church Society chair George Curry.

"The Bible tells us same-sex relationships are always sinful and wrong ".

"Ideally, what you want to do is find an environment where this child and any child can be looked after by heterosexual parents.

"Any Christian leader who hears of a clergyman in sexually active same-sex relationship must be disciplined. We cannot have our leaders endorsing immorality."

'Crisis point'

In September, the outgoing Archbishop of Canterbury Dr George Carey raised concerns the Church was being "steadily undermined by dioceses and individual bishops taking unilateral action ... in matters to do with sexuality".

Dr Carey, who steps down from the post later this week, said the growing chasm between the traditionalists and the liberals in the Anglican faith was his "greatest worry" and had brought the Church to "crisis point".

George Carey fears breakaway Church factions

The archbishop's representative on the Church in Wales child protection panel, Dr Heather Payne, said Mr Curry was "trying to make a hostage to fortune out of Dr Williams".

"[Many] foster children have major problems ... and are children in distress.

"We are looking for is people able to help support them, build their resilience and deal with any challenging behaviour.

"It is simply inadequate to focus on one aspect of somebody's behaviour and say 'that qualifies you or doesn't - that is not the way foster carers are approved."

On Sunday, in his last sermon as Archbishop of Canterbury, Dr Carey wished Dr Williams good luck as his replacement, denying his successor is "somehow in a different part of the Church".

In May, MPs paved the way for gay couples to adopt when a Conservative motion to exclude same-sex adoptions was defeated.

The Adoption and Children Bill is currently being read in the House of Lords.