A PUSH to allow lesbians access to IVF is undermining the traditional family and writing off fathers, Liberal MP Martin Hamilton-Smith says.

Labor MP Ian Hunter has introduced a Bill to Parliament to allow fertile same-sex couples, or single women, to access assisted reproductive technology.

It has passed the Upper House on a conscience vote and is being debated by Lower House MPs. Only women deemed infertile can now access IVF, which is part government-funded.

Mr Hamilton-Smith has spoken against the Bill, saying he is "standing up for the role of the father in child rearing".

A father of a son, stepson and stepdaughter himself, Mr Hamilton-Smith said the proposed law was "undermining the fabric of society... undermining the family unit as it has traditionally been known".

He said it would allow a woman to "go out and, through an act of technology, have a child out of wedlock without any father being involved at any time".

"They can decide to just go off and have a baby using IVF... I am just going to have this child; it is all about me... I think there is something wrong about that," he said.

While Mr Hamilton-Smith said gay relationships "deserve to be valued and accepted by the community" he stopped short of supporting gay marriage or access to IVF.

Catholic Archbishop of Adelaide Philip Wilson urged other MPs not to support the Bill because a child's rights should come before an adult's desire to be a parent.

"Children are entitled, whenever possible, to know, love and be cared for by both their mother and father," he said.

Mr Hunter said research showed the "parental make-up of families has very little impact on outcomes for a child" and what mattered was a loving environment.

Flinders IVF marketing manager Joe Leborec said the reproductive centre had been providing services to same-sex couples for almost a year through its interpretation of the definition of infertility.

"The key is the inability to father a child, so by definition (lesbian couples) are infertile because neither of the two patients can father a child," he said.

Originally published as IVF for lesbians 'a threat to men'