One of the most persuasive weapons in the arsenal of supporters of embryonic stem cell research is fear of losing highly qualified scientists to countries or states with more liberal regulations. It is often claimed that the US will experience a brain drain because of its policies are, in the main, more restrictive than in the UK or Europe. Similarly, Australians fret about a brain drain to the US, and UK scientists have been lured to Singapore.

An article in Nature Biotechnology has attempted to turn anecdotal evidence of this into hard statistics. The researchers found that US stem cell scientists are significantly more likely than biomedical colleagues in less contentious fields to have received job offers, especially from overseas institutions. However, "too few international offers were reported to draw firm conclusions". In any case, the mere offer of a job does not necessarily result in a job change. Surprisingly, despite some high-profile moves, the fear is still not a fact.