Which is an example of how stem cells are currently being used? for generating healthy cells to form replacement organs like brains for directing differentiation to treat diabetes and arthritis for testing for possible side effects of a new cancer medication for curing heart disease by regenerating damaged heart tissue

Curing heart disease by regenerating damaged heart tissue.

for curing heart disease by regenerating damaged heart tissue

Stem cells are commonly used for the tissue repair process and they have the potentials to develop into different cells type in the body during early life and growth. Thus, stem cells in many tissues can function as internal repair system by dividing essentially without limit to replenish other cells as long as the person or animal is still alive. Furthermore, they mediates diverse role in disease progression, development and tissue repair processes in host.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."