With only three living individuals left on this planet, the northern white rhinoceros (Ceratotherium simum cottoni) could be considered doomed for extinction. It might still be possible, however, to rescue the (sub)species by combining novel stem cell and assisted reproductive technologies.
Poaching has slashed the rhinos’ numbers from around 2,300 in the 1960s. For the remaining three animals, natural reproduction is not an option. Sudan, a 42-year-old male, has a low sperm count; his 26-year-old daughter Najin has leg injuries that mean she cannot bear the weight either of a mounting male or of pregnancy; and her daughter Fatu has a uterine disorder that would prevent an embryo from implanting. But sperm and other cells from another ten individuals are in frozen storage.
http://www.nature.com/news/stem-cell-plan-aims-to-bring-rhino-back-from-brink-of-extinction-1.19849 [nature.com]
http://onlinelibrary.wiley.com/doi/10.1002/zoo.21284/abstract [wiley.com]