A few weeks ago I was attending Mass in St. Stephen's church in England. In Princeton I am presbyterian, but in England I am catholic because I go to Mass with my sister. The reading from the gospel of St. Matthew told of the angry Jesus driving the merchants and money-changers out of the temple, knocking over the tables of the money-changers and spilling their coins on the floor. Jesus was not opposed to capitalism and the profit motive, so long as economic activities were carried on outside the temple. In the parable of the talents, he praises the servant who used his master's money to make a profitable investment, and condemns the servant who was too timid to invest. But he draws a clear line at the temple door. Inside the temple, the ground belongs to God and profit-making must stop.

While I was listening to the reading, I was thinking how Jesus's anger might extend to free markets in human bodies and human genes. In the time of Jesus and for many centuries afterwards, there was a free market in human bodies. The institution of slavery was based on the legal right of slave-owners to buy and sell their property in a free market. Only in the nineteenth century did the abolitionist movement, with Quakers and other religious believers in the lead, succeed in establishing the principle that the free market does not extend to human bodies. The human body is God's temple and not a commercial commodity. And now in the twenty-first century, for the sake of equity and human brotherhood, we must maintain the principle that the free market does not extend to human genes. Let us hope that we can reach a consensus on this question without fighting another civil war. Scientists and religious believers and physicians and lawyers must come together with mutual respect, to achieve a consensus and to decide where the line at the door of the temple should be drawn.

Like all the new technologies that have arisen from scientific knowledge, biotechnology is a tool that can be used either for good or for evil purposes. The role of ethics is to strengthen the good and avoid the evil. I see two tremendous goods coming from biotechnology in the next century, first the alleviation of human misery through progress in medicine, and second the transformation of the global economy through green technology spreading wealth more equitably around the world. The two great evils to be avoided are the use of biological weapons and the corruption of human nature by buying and selling genes. I see no scientific reason why we should not achieve the good and avoid the evil. The obstacles to achieving the good are political rather than technical. Unfortunately a large number of people in many countries are strongly opposed to green technology, for reasons having little to do with the real dangers. It is important to treat the opponents with respect, to pay attention to their fears, to go gently into the new world of green technology so that neither human dignity nor religious conviction is violated. If we can go gently, we have a good chance of achieving within a hundred years the goals of ecological sustainability and social justice that green technology brings within our reach.