The professor of psychiatry at the Mater Hospital/UCD, Prof Patricia Casey, has said "one of the strangest inconsistencies and contradiction" today was "the disjunction that some politicians make between their private views and their public stance on abortion."
"Is there any other behaviour where such inconsistent hypocrisy would be allowed and even lauded," she asked.
Speaking at a conference on "Cherishing human life . . . exploring today's ethical issue" in Dublin at the weekend, she said: "Take John Kerry, the would-be Democratic contender for the US presidency. He has stated that as a devout and practising Catholic he personally is opposed to abortion but as president he will not row back on the Roe v Wade decision (which allowed abortion in the US) in nominating his appointees to the Supreme Court."
"He has stood on platforms with pro-choice groups restating his view that women have a right to choose - even though he personally doesn't agree with this," she said.
She asked: "What other issue is there in which one's moral beliefs should not be used as a guiding compass? The whole point of beliefs is that they inform our behaviour and guide us in our journey to try and better the world.
"Presumably if one is opposed to abortion or to anything else for that matter we do so because we believe it is not for the good of society or humanity. Yet many of those who claim the personal ethic of being opposed to abortion believe that a woman should have the right to choose abortion whenever and for whatever reason she decides.
She instanced the example of female circumcision. "Suppose I said that I oppose this but I would march on the streets in order to allow countries to legislate for this practice. Or something more pertinent to us in the West - nuclear weapons.
"What if I said I personally oppose their use but I absolutely support the right of my government to use them and I would march in support of that right. I would rightly be called a two-faced sham, an inconsistent, weak-kneed moral pygmy," she said.
Time was running out "on the unthinking and uncritical acceptance of abortion", she said.