Letter of Transmittal to the President 
xii 
Mr. President, allow me to join my Council colleagues and 
our fine staff in thanking you for this opportunity to offer you 
and the American people what we hope is a useful and 
constructive review of where things stand, both in the 
laboratory and in the public arena, with regard to this 
promising and ethically challenging area of research. 
Sincerely, 
Leon R. Kass, M.D. 
Chairman 
PRE -PUBLICATION VERSION 
