Sir

After 11 September 2001, the United States adopted precautionary measures to protect its people and institutions. Many institutions have slammed their doors to Muslim scientists. As a scientist and writer interested in science and society, I am concerned that the current political and emotional upheavals will severely handicap the growth of science in the Islamic world.

Discriminatory US policies discourage US institutions from recruiting Muslim scientists. These policies include the US Department of Agriculture's ban on scientists from several countries including traditional Islamic areas; extensive background checks on Muslims; and the recent law requiring men from Islamic countries to report to immigration offices.

These exclusion policies cover a broad range of science, from agriculture to IT, and will severely inhibit the growth of science in the Islamic world. To avert catastrophe, all groups — Muslims, Americans and Europeans — must act.

Muslims must recognize the need to spend petrochemical wealth in establishing centres of scientific excellence and creating an environment conducive to scientific growth in all Islamic countries (not just Arab ones). Muslim nations must formulate relevant R&D programmes, restructure institutions to end corruption and dynastic practices, and collaborate with both Western and newly industrialized states to nurture a strong science base. Finally, Muslims must demand more from their leaders, so that they can become equal to other societies.

US organizations and individual scientists must lobby hard to change post-11 September policies that are detrimental to scientific endeavour. US scientists could collaborate, mentor and otherwise assist Muslim scientists. American Muslim scientists must take the lead in Islamic science, as they live in a progressive country.

Europeans can take an active role in bridging the rift between the US and Muslim worlds, filling the vacuum created by US precautionary policies. Europeans are already taking small steps to collaborate with the Arab countries (Nature 423, 906; 200310.1038/423906b). This process should be encouraged.

There is an urgent need to reinvigorate the rusted scientific sector of the Muslim world beyond rhetoric, marathon conferences and establishment of skeleton institutions. It requires the concerted effort of politicians, scientists, philanthropists, entrepreneurs and ordinary citizens. There is definitely room for reform and business opportunities in the Islamic world.

The United States was brutally hurt by a few ruthless terrorists, and faces further threats. However, blanket repressive policies in response will cause more harm than good to the world as a whole.