Mr Duncan Smith says children need the influence of a father
MPs have voted to scrap laws forcing clinics to consider the need for a "father and mother" before allowing women to seek IVF treatment.
Iain Duncan Smith led the cross-party bid, saying the absence of a father had a "detrimental effect" on a child. His plan was defeated by 292 votes to 217.
Currently, IVF clinics have to consider the "welfare" of any child created, including the need for a father.
But the government wants the focus instead on "supportive parenting".
MPs also opposed a further bid to ensure there is a "father or a male role model" before fertility treatment, by 290 votes to 222.
The issue of the role of fathers in IVF comes in the second day of committee stage debate of the controversial Human Fertilisation and Embryology Bill, aimed at updating laws from 1990.
Later MPs will debate and vote on whether to cut the 24-week upper limit for abortions to 20 weeks or less.
Ex-Tory leader Mr Duncan Smith led the charge to keep the status quo in conditions for IVF treatment - that the need for a father, and a mother, is considered.
"On the whole the absence of fathers generally has a detrimental effect on a child, and it's the vast majority that are going to be a positive influence - if they are connected to that family," he said.
He said the influence of a father figure was as important for daughters as it was for sons.
"It is more often from the father that those young girls learn about empathetic, non-conditional love - that it's possible to have a relationship that doesn't have to involve sex," he said.
Labour ex-minister George Howarth asked if he accepted that there were bad fathers who can "have a bad influence in some circumstances" - to which Mr Duncan Smith said he did.
Lib Dem science spokesman Evan Harris asked: "Do you consider lesbian couples to be broken families? And if you do, what evidence to you have that the children of those families are going off the rails?"
Mr Duncan Smith said he did not consider them broken families. "I hope, like everybody else, we would want any such relationship to prosper and the child would benefit."
He said he did not know of any gay or lesbian couples who had been refused treatment under the current rules.
But Labour's Emily Thornberry said the Birmingham Women's Hospital insisted couples needed to be in a heterosexual relationship for two years.
"That's direct discrimination against lesbian couples and against single women," she said.
Tory shadow health minister Mark Simmonds said Human Fertilisation and Embryology Authority guidelines were not allowed to refuse treatment on the basis of sexual discrimination.
Labour's Geraldine Smith, who backs Mr Duncan Smith's stance, said: "It's nonsense to suggest that we shouldn't take into account the need for a father.
"We are not suggesting that single women or lesbians do not have IVF treatment - the only thing we're saying is there's a father figure somewhere.
"It's just pure common sense."
But Tory veteran Sir Patrick Cormack insisted: "We should not, out of a misguided concept of equality or fairness, pretend that there is an automatic right for anyone to have a child, regardless of sex.
"A child that is deliberately brought into the world with no desire that there should be a man or a woman who is the parent is brought in with a disadvantage."
However, Health Minister Dawn Primarolo insisted that the legislation "should be for all people that seek treatment, whether in a same sex couple, single women or heterosexual couples".
"It's clear that if the need for a father was retained, the legislation would place additional burdens on single women and same sex female couples.
"There is no evidence or suggestion to say that these women do not make good parents - that these women somehow make bad parents and therefore should be required to do additional steps."
She said the important issue was the "welfare of the child". "It's the quality of the parenting that makes the most difference, not the gender of the parents as such."
On Monday, MPs voted down a cross-party attempt to ban hybrid human animal embryos.
Roman Catholic cabinet ministers Ruth Kelly, Des Browne and Paul Murphy voted for a ban, while Prime Minister Gordon Brown and Tory leader David Cameron both opposed it.
A bid to ban "saviour siblings" - babies selected to provide genetic material for seriously ill relatives -was also voted down.