Blastocyst Complementation: The New Kid on the Xenotransplantation Block.

The transplantation of genetically modified pig organs and tissues is arguably the most promising approach to overcoming the world-wide shortage of organ and tissues for transplantation. The advent of gene editing has seen a resurgence in interest in this approach which has also allowed blastocyst complementation to be explored as an alternative to solving this challenge. Genetic strategies are increasingly being used to explore this possibility and overcome the many scientific hurdles this presents. While blastocyst complementation faces many scientific challenges the ethical questions surrounding this approach are equally important and will need to be addressed at the same time, if this new kid on the xenotransplantation block is to become a reality.