A debate over embryonic stem-cell research in the shadow of a Nazi past has left German scientists afraid that they will be left behind in the race to develop therapies.
Otmar Wiestler and Oliver Bruestle, of the Institute for Neuropathology at Bonn University, want to import embryonic stem cells to continue researching a therapy for multiple sclerosis.
German law forbids research on human embryos and their creation other than by in vitro fertilisation for childless couples. But there are no restrictions on importing stem cells.
Professor Wiestler and Professor Bruestle have agreed to put their work on hold until they have clear political backing.
"Because of our history, the debate here is very emotional. That is why we need the backing of politicians, our university ethics commission and the DFG (German Research Council)," Professor Wiestler said.
The scientists' research hit the headlines earlier this year when Wolfgang Clement, Social Democrat premier of the state of North Rhine-Westphalia, negotiated a cooperation agreement between Bonn and Haifa universities.
This opened the door to stem cells being imported from Israel, where stem-cell research is widely accepted.
Mr Clement's state, in which Bonn lies, has the largest concentration of biotechnology companies in Germany.
The agreement has highlighted the political battle lines. The Greens, junior coalition partners in the North Rhine-Westphalian assembly as well as in the national government, generally side with religious conservatives in opposing stem-cell research, driven by fears of commercial biotechnology and memories of Nazi eugenics, euthanasia and selection.
Chancellor Gerhard Schroeder, a political ally of Mr Clements, wants to manage the politics of scientific ethics through a National Ethics Council. This is due to report to parliament in autumn.
The DFG, the main research funding agency, will decide by December 7 whether to grant public funds for Professor Wiestler and Professor Bruestle's research.