"I don't propose certain topics which I consider taboo. Unless we are asked, we had better not mention them."
In particular, Arber is uncomfortable with the Vatican's insistence that condoms aren't the right way to prevent the spread of HIV/AIDS, which he says is "unrealistic." The Church maintains that condoms promote promiscuity. Both the World Health Organization and the United Nations regard condoms as highly effective at preventing the spread of HIV/AIDS, which kills over a million people globally every year.
Arber euphemistically says he's hopeful that Pope Francis will help the Church "move things forward" when it comes to tackling HIV/AIDS.
Jeremy Webb, editor-in-chief of New Scientist magazine, also hopes the Catholic Church under Pope Francis will make an exception to its stance on condom use to fight the global HIV/AIDS epidemic.
He says the speed at which new developments are emerging in the biological sciences is increasingly bringing about conflicts with the Vatican. In particular Webb sees this in relation to reproductive technologies -- such as in vitro fertilization, and egg and sperm donation -- all of which the Church says are improper methods of procreation.
"The church is taking its viewpoint from 2,000-year-old teachings and trying to apply them to a modern world, which is delivering all sorts of moral dilemmas," he said to CNN.
Webb doubts there will be any significant change in the Vatican's fundamental attitude to contraception under Francis and believes this will remain a sticking point between the biological sciences and the church.
"Catholics believe that anything that threatens the sanctity of life -- including contraception -- is wrong. That is a barrier and it will always be a barrier."
There have been no signals yet as to whether Pope Francis will bring about a softening of the Vatican's stance on issues such as condom-use as means to prevent suffering and early death.
Werner Arber is optimistic that the Vatican will eventually catch up with the scientific evidence: "I have hope but - as with Galileo -- it will take a long time."