The Archbishop of York last night led a powerful cross-party attack by peers on plans to make it easier for lesbian couples to become parents through fertility treatment.
The Most Rev John Sentamu told the Lords that the changes in the Human Fertilisation and Embryology Bill put the right to have a child ahead of the welfare of the child.
However the second reading debate in the upper chamber had to be dramatically suspended after Labour peer Lord Brennan collapsed shortly after delivering his speech.
The 65-year-old QC was given a heart massage by, among others, Health Minister and leading surgeon Lord Darzi of Denham - who had himself opened the debate for the Government.
Lord Brennan was treated in the Lords chamber by first aid and ambulance staff, using an oxygen mask and an intravenous drip, before being taken out on a stretcher and transferred to nearby St Thomas's Hospital.
A hospital spokesman said tonight that his condition was "stable".
Earlier, the debate had focused on a clause in the Bill which removes references in earlier legislation on the conditions for licenses for in-vitro fertilisation treatment, to "the need of that child for a father".
Dr Sentamu said the change amounted to "the removal by design" of the father of the child.
"It appears to me to send a signal that everyone has a right to a child and that this right overrules consideration of that child's welfare," he said.
"The Government's reponse is not based on the welfare of the child but rather on the desire of those who feel they should have a child 'of rights', without the need of a father.
"The rights of a prospective parent of a child must not triumph over the welfare of the children. "
He was backed by the former chairman of the Human Fertilisation and Embryology Authority, Baroness Deech, who called on ministers to revert to the "careful and sensitive compromise" originally worked out in 1990.
"I think it would be extraordinary if this House were to ignore the contribution made by half of the human race towards the upbringing of the next generation," she said.
"It is important that this House should reaffirm the importance of parenting, both mothering and fathering. "
Liberal Democrat Baroness Williams of Crosby, a former Labour Cabinet minister, warned that the Bill, as currently worded, could negatively change the public's "attitude towards fatherhood".
She said: "Unless we give men a full sense of what it is to be a father and a member of a family we are simply going to find ourselves with more and more families that are dysfunctional and boys who don't quite know what their place is within society and the family. "
Opening the debate, Lord Darzi said the aim of the Government was to ensure the law remained "effective and fit for purpose" into the 21st century.
The Bill would "update the regulation of assisted reproduction to ensure it is both effective and also reflective of modern society", including "legal recognition for different family forms".
"The Bill includes clear recognition of same-sex couples as legal parents of children conceived through use of donated sperm, eggs or embryos," he said.
"This would mean, for example, that the woman who gave birth and her civil partner would both be recognised as parents of the child conceived by assisted reproduction. "Reuse content