Conservative MP Jacob Rees-Mogg says he is “completely opposed” to abortion, including in cases of rape or incest.
The backbencher told ITV’s Good Morning Britain that abortion was “morally indefensible”.
“Life is sacrosanct and begins at the point of conception,” he said.
The North East Somerset MP has recently faced questions about his leadership ambitions, dismissing reports linking him with the job as “jolly August stuff”.
Appearing on Good Morning Britain, he again distanced himself from leadership talk, before being asked for his views on same-sex marriage, which he opposes.
“I am a Catholic and I take the teachings of the Catholic Church seriously,” he said.
“Marriage is a sacrament and the decision of what is a sacrament lies with the Church not with Parliament.”
The Church’s teachings on faith and morals were “authoritative”, he said, but he added it was not for him to judge others.
However, he said he was completely opposed to abortion.
“With same-sex marriage, that is something that people are doing for themselves,” he said.
“With abortion, it is something that is done to the unborn child. That is different.”
Asked whether his opposition applied in cases of pregnancies resulting from rape or incest, he replied: “I’m afraid so.”
Mr Rees-Mogg said women’s abortion rights under UK law were “not going to change”.
He also said his party was more tolerant of religious views than the Liberal Democrats, whose former leader Tim Farron quit after facing repeated questions about his views on gay sex.
“It’s all very well to say we live in a multicultural country… until you’re a Christian, until you hold the traditional views of the Catholic Church, and that seems to me fundamentally wrong,” Mr Rees-Mogg said.
“People are entitled to hold these views.”
He added that the “democratic majority” were equally entitled to laws that did not follow the Catholic Church’s teaching.
The British Pregnancy Advisory Service said Mr Rees-Mogg’s “extreme” views were “wildly at odds” with public opinion.
Their head of policy research Katherine O’Brien said: “We are a pro-choice country, we have a pro-choice Parliament.
“Every politician is entitled to hold their own opinion on abortion. But what matters is whether they would let their own personal convictions stand in the way of women’s ability to act on their own.”
A spokesman for Theresa May said the PM did not agree with Mr Rees-Mogg but said that it was a “long-standing principle” that abortion was a “matter of conscience” for individual MPs to decide on.