The conservative senator Cory Bernardi has hinted at the possibility of taking legal action against a fellow Liberal party member who questioned his “obsession” with gay people.

On Monday the prime minister, Tony Abbott, sought to distance himself from Bernardi after the South Australian senator used a new book to argue that abortion choice advocates were "pro-death", that children raised by single parents were more likely to be promiscuous and law breakers and that alternatives to traditional marriage would cause “social chaos”.

But the north Queensland Liberal MP Warren Entsch, who has a record of advocating on behalf of same-sex couples, has since offered a more vigorous response, raising concern over Bernardi’s “obsessions” with gay people. He asked whether Bernardi would advocate sterilisation if a member of his family turned out to be gay.

“It worries me,” Entsch told Fairfax Media in a story published on Wednesday. “You've really got to watch out for those that have these obsessions. He who protests the loudest …”

Entsch also said that as a stepfather he was offended by Bernardi's comment that a biological mother and father who were married represented the ''gold standard'' for children's development.

News Corp Australia quoted Bernardi as saying he had no comment about Entsch’s criticism “as the lawyers are having a look at it”.

“I have learned never to have public spats with colleagues who speak of books they haven't read,” he told a journalist via text message. "It's generally a waste of time."

Guardian Australia asked Bernardi to confirm he was speaking to his lawyers about the issue, but he replied with a text message saying

“I have no comment”.

Comment is being sought from the prime minister’s office about the public disagreement between party colleagues and the possibility of defamation action.

On Monday, following calls from Labor and the Greens to condemn Bernardi over the book, Abbott’s spokeswoman issued a short statement that said: "Senator Bernardi is a backbencher and his views do not represent the position of the government.”

Bernardi – who stood down as parliamentary secretary to Abbott in 2012 after suggesting that legalising same-sex marriage might prompt calls to allow bestiality – has long railed against what he has described as political correctness.

His book – The Conservative Revolution – attracted a range of sarcastic and critical public reviews on Amazon.

In the book, Bernardi notes the increasing number of “non-traditional” families and says there is “a temptation to equate all family structures as being equal or relative”.

"Why then the levels of criminality among boys and promiscuity among girls who are brought up in single-parent families, more often than not headed by a single mother?” he writes.

"What is missing in the push for human cloning, in-vitro fertilisation and surrogacy, for example, is the understanding that children come into families as gifts, not commodities.

"It is perfectly reasonable and rational, therefore, for the state, if it is to have a role in social policy and the affairs of marriage, to reinforce and entrench those aspects of traditional marriage that work, not undermine them and promote 'alternatives' which have led to social chaos.

"Competent social policy should be drafted by those who understand the primacy of natural law and who are able to see patterns in society."

Entsch, a former chief opposition whip, said he was a step-father and cited the strength of his love for his daughter. “The love that I have in my family is as strong a bond as anybody's,” he told Fairfax Media.

Entsch said the communications minister, Malcolm Turnbull, was not a lesser person despite having been raised by his father. ''Is he a second-grade citizen because of that? I don't know how many charges Malcolm's been on,” he said.

He was also quoted as criticising Bernardi’s views on abortion as “nonsense”, asking whether Bernardi would oppose abortion following rape or incest. A large majority of the Liberal party took issue with Bernardi's views, Entsch said.

''I am elected to represent all of my constituents and it's not for me to be judgmental,'' he said.

In an interview on Monday, Bernardi said he did not want to ban abortion but "there is a right to life issue we should be exploring" and he believed life began at conception.

Bernardi described himself as a "faithful son of the Liberal party" and said he was entitled as a backbencher to speak free of cabinet restrictions and contribute to the battle of ideas.

"They're not far-right views at all; they're enduring views," Bernardi told the ABC on Monday.

"What I would suggest to you is the fact they are controversial, according to elements of the media and sections of the public, suggests just how far we've come. These are very traditional views; they're views that have stood the test of time and they've been developed over successive generations ... The eroding of our cultural institutions, our values and our ethics has consequences for society."