Peers have backed the government over gay equality laws at the centre of a row with the Catholic Church.
The draft regulations are being debated in the Lords
They voted against an amendment to throw out the Equality Act (Sexual Orientation) Regulations, brought by Tory peer Baroness O'Cathain.
She argued that they were "seriously flawed" and would lead to litigation, but was defeated by 168 votes to 122.
Among implications are that Catholic adoption agencies would be forced to place children with gay couples.
The Equality Act (Sexual Orientation) Regulations, which outlaw discrimination against gay people by businesses and service providers, and have already been approved by MPs, will now come into force on 30 April.
But they have proved extremely controversial.
The Catholic Church has said it will be forced to shut its adoption agencies, which handle some of the most difficult-to-place children, rather than act against church teachings.
Some backbench Tory MPs have complained that the draft regulations were being "rail-roaded" through Parliament with "unseemly haste".
Several hundred peers turned up for the debate in the Lords on Wednesday. Conservative peers were allowed a free vote as it was an "issue of conscience".
Lady O'Caithain told peers: "I believe the regulations are seriously flawed.
"The Commons has had no opportunity to debate them, other than in a hastily arranged committee off the floor of the House.
"This surely is not acceptable. The government is rushing headlong into the incredibly sensitive area of a clash between gay rights and religious freedom and doing so by secondary legislation that does not allow for amendments and permits only very limited debate."
Her amendment warned that the draft regulations will "result in litigation over the content of classroom teaching".
But Baroness Andrews, for the government, asked peers to reject the amendment.
She said: "This has been a long journey to us recognising the rights of people irrespective of sexual orientation. It is a historic step forward towards dignity, respect and fairness for all."
At prime minister's questions earlier, Tony Blair said critics were effectively backing discrimination.
Tory MP Bill Cash told him: "You have given more preference to those who stand for gay rights than those who are concerned with conscience, with family and with religion."
But Mr Blair denied the equality laws were being "rail-roaded" through Parliament, saying there had already been much debate.
Mr Blair said there had been much debate about the laws
The government has refused to grant Catholic agencies an opt-out, but will give them a 21-month transitional period to prepare for the new laws.
The hope is that extra time would allow expertise and knowledge to be passed onto the secular sector, rather than being lost altogether.
Cardinal Cormac Murphy-O'Connor, the most senior Catholic in England and Wales, has said it "remains to be seen" whether the church will cooperate.
Forty-two lay members of the Church of England's General Synod had written to bishops in the Lords asking them to oppose the measures in Wednesday's debate.
The Equality Act is due to come into effect in England, Wales and Scotland in April.