Xenotransplantation is any procedure that involves the transplantation, implantation or infusion into a human recipient of live cells, tissues, or organs from a nonhuman animal source; or human body fluids, cells, tissues or organs that have had ex vivo contact with live nonhuman animal cells, tissues or organs
Benefits:
Not only does the demand for human organs far exceed the supply, recent evidence has suggested that transplantation of cells and tissues may be therapeutic for certain diseases, where human materials are also not usually available.
Drawbacks: While xenotransplantation benefits are considerable, significant concerns exist with respect to the potential infection of recipients with both recognized and unrecognized infectious agents, as well as the possible subsequent transmission to their close contacts and into the general human population.
Also, of public health concern is the potential for cross-species infection by retroviruses, which may be latent and lead to disease years after infection.
More information is available at:
http://www.fda.gov/BiologicsBloodVaccines/Xenotransplantation/default.htm
