Table 3.

Advantages and disadvantages of adult and embryonic stem cells.

AdvantagesDisadvantages
Human ES cells Can make virtually any tissue (in theory) Allogeneic only (currently) 
 Some tissues “easy” to generate (e.g., cardiac) Teratoma formation? 
 Can be propagated indefinitely Differentiation conditions to be established 
 Amenable to genetic manipulation? Some tissues difficult to generate (blood) 
  Ethical issues 
Adult stem cells Autologous Most have limited self-renewal 
 Many types and sources Differentiation outside lineage? (maybe) 
 Some types have extensive self-renewal potential Autologous (use more cumbersome and expensive) 
 Not tumorigenic  
 Default differentiation  
 Amenable to gene transfer  
 Potential delivery methods attractive  
 No ethical issues  
AdvantagesDisadvantages
Human ES cells Can make virtually any tissue (in theory) Allogeneic only (currently) 
 Some tissues “easy” to generate (e.g., cardiac) Teratoma formation? 
 Can be propagated indefinitely Differentiation conditions to be established 
 Amenable to genetic manipulation? Some tissues difficult to generate (blood) 
  Ethical issues 
Adult stem cells Autologous Most have limited self-renewal 
 Many types and sources Differentiation outside lineage? (maybe) 
 Some types have extensive self-renewal potential Autologous (use more cumbersome and expensive) 
 Not tumorigenic  
 Default differentiation  
 Amenable to gene transfer  
 Potential delivery methods attractive  
 No ethical issues