Final answer:
Embryonic stem cells can be customized to possess the same genetic makeup as the patient through ex vivo gene therapy or cloning human embryos.
Step-by-step explanation:
It is possible to "customize" ES cells (embryonic stem cells) so that they possess the same genetic makeup as the patient. This can be done using ex vivo gene therapy or by cloning human embryos. In ex vivo gene therapy, somatic cells from the patient are collected and grown in culture. These cells are then transfected with retroviral cloning vectors containing the desired gene.
The selected cells are then transplanted back into the patient. In cloning human embryos, the DNA from an adult human is introduced into a human egg cell and stimulated to divide. The resulting embryonic stem cells have the capacity to develop into various cell types.