sentences:  In 2015, however, tests conducted by Czech specialists revealed that neither of the females are "capable of natural reproduction".According to the director of the Dvůr Králové Zoo, it was possible Najin became pregnant but miscarried shortly after, which resulted in pathological changes in its uterus, preventing another impregnation.At the end of 2015, scientists from the Leibniz Institute for Zoo and Wildlife Research, San Diego Zoo Global, Tiergarten Schönbrunn, and Dvůr Králové Zoo developed a plan to reproduce northern white rhinos using natural gametes of the living rhinos and induced pluripotent stem cells.