Early development in humans is characterised by low and variable embryonic viability. reflected in low fecundity and high rates of miscarriage. relative to other mammals. Data from assisted reproduction programmes provides additional evidence that this is largely mediated at the level of embryonic competence and is highly heterogeneous among embryos. https://www.roneverhart.com/Ryukyu-Kobujutsu-Buki-Jutsu-Vol-2-DVD-with-Kiyoshi-Yogi/