THE JOHNS HOPKINS UNIVERSITY 
SCHOOL OF MEDICINE 
and 
THE JOHNS HOPKINS HOSPITAL 
I 
I department of pediatrics 
JOHN W. LITTLEFIELD, M.D. 
Chairman and Pediatrician-in-Chief 
Mailing Address: 
The Children's Medical & Surgical Center 
THE JOHNS HOPKINS HOSPITAL 
Baltimore, Md. 21205 
Tel: (301) 955-5976 
I 
October 4, 1984 
William J. Gartland, M.D. 
Executive Secretary, RAC 
National Institute of Allergy 
and Infectious Diseases 
National Institutes of Health 
Bethesda, MD 20205 
Dear Bill: 
From several directions I have heard of Mr. Jeremy 
Rifkin's letter of August 21, 1984 suggesting a prohibition 
on the transfer of genes between any mammalian species and 
the germ line of another. I am writing in order to be 
included in the opposition to such a prohibition. It is 
unreasonable in my opinion to object to introducing human 
genes into the eggs of mice or other non-human mammals. 
Such work is clearly essential if we are to learn how 
development is controlled and how birth defects might be 
prevented. It is already providing much new information, 
with eventual clinical relevance, concerning how genetic 
information is regulated during embryogenesis, a subject 
which has previously been a complete mystery. The gulf 
between those caring for patients with birth defects and 
those studying development in the laboratory is very deep 
and wide. It would seem to me extremely foolish to 
discourage this exciting and valuable new avenue of medical 
research. 
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