The Government tonight comfortably beat off a fresh challenge to its flagship Bill updating fertility laws for the first time in 20 years.
On a free vote, MPs rejected a cross-party move for doctors to consider the need for a father in offering fertility treatment.
Under the Human Fertilisation and Embryology Bill at present, IVF clinics would only have to take account of the need for "supportive parenting".
Voting was 292 to 217, majority 75.
Critics claim the change, led by Tory former leader Iain Duncan Smith with backbench Labour support, would have discriminated against lesbian and gay people.
Later tonight there will be a series of crucial votes on the emotive issue of lowering the abortion time limit.
In a highly-charged three-hour debate, Mr Duncan Smith said it was essential to recognise the importance of a father figure to a developing child.
The "paramount point of consideration" should be the rights of the child.
He added: "This is common sense. All we are saying is 'take consideration of the need of a child for a father' not 'if you don't have a father you will never get treatment'.
Labour's David Taylor (NW Leicestershire), backing the move, said it was "perverse" to "write the father out of the script".
Geraldine Smith (Morecambe and Lunesdale), another Labour supporter of the amendment, told Mr Duncan Smith: "To most people outside this House you are just talking common sense. They would wonder why we are even having this debate.
"Is there any wonder people think politicians are out of touch with ordinary people when we have debates such as this.
"It's nonsense to suggest that we shouldn't take into account the need for a father."
But Labour's Emily Thornberry (Islington S and Finsbury) warned any move away from the Government's "carefully thought out" wording would cause increased confusion.
"I always worry when people start saying they are only applying common sense, because so often common sense is a cover for discrimination, narrowness and an inability to face the 21st century."
She said: "You will not, as a result of this amendment, bring any more fathers into any more families.
"The important point is to give legal rights to lesbian couples and single women."
She added: "It's wrong to make judgments about families and tell one family they are normal and another family that they are abnormal.
"It is wrong to vilify single parents. It is wrong to discriminate against lesbian couples."