The Senate has passed a motion calling for federal ministers to boycott a controversial conference that endorses anti-abortion and anti-gay marriage messages.

Social Services Minister Kevin Andrews is opening the World Congress of Families in Melbourne on Saturday.

A spokeswoman for the Minister said it is a conference about families and fits within his portfolio.

American breast cancer surgeon Angela Lanfranchi, who has linked abortion and breast cancer, is one of the speakers.

The World Congress of Families' website promotes marriage between a man and a woman because they have "complementary natures".

The organisation also endorses the right to life "from fertilisation to death".

Greens Senator Larissa Waters moved a motion in the Senate to urge Mr Andrews and any other Government MPs planning to attend the conference to cancel.

"By opening the conference, Minister Andrews is legitimising the prejudiced, bigoted ideals of the World Congress of Families," she said.

"The Abbott Government and its backward views are completely out of touch with the Australian community."

The motion to the Senate was endorsed without the need for a formal vote.

Abortion 'a risk factor like any other'

Dr Lanfranchi has defended her conclusions about the link between breast cancer and abortion during a media event at Federal Parliament on Thursday.

The office of Family First Senator Bob Day signed the group into the restricted area of parliament to hold the media event.

"I don't know why it's stirred up discontent; it's a risk factor like any other," Dr Lanfranchi said.

"Women need to know that information so that they can make choices, and informed choices."

Another Cabinet Minister, Eric Abetz, sparked debate over Dr Lanfranchi's views in a Channel 10 interview earlier this month, when he appeared to endorse the doctor's research.

"I think the studies, and I think they date back from the 1950s, assert that there is a link between abortion and breast cancer," he said.

At the time, head of the Australian Medical Association Brian Owler disputed the research.

"I think it needs to be made very clear that there are very robust studies, international studies, which have discredited any link between abortion and breast cancer," he said.

"There is no link between abortion and breast cancer. We need to make that very clear to the public, and certainly we should not be promoting any papers from the 1950s."

Senator Day's office said he will not be attending the Family Congress in Melbourne but was happy to provide Dr Lanfranchi direct access to reporters and politicians.

In a statement, Senator Day said he supports free speech and "Dr Lanfranchi expressing her professional opinion".