For generations, Chinese intellectuals have emphasized close ties between the state (guojia), the nation (minzu), the population (renkou), the Han race (zhongzu), and, more recently, the Chinese gene-pool (jiyinku). Traditional Chinese medicine focused on preventing birth defects, promoting maternal health and "fetal education" (taijiao) during pregnancy, and nourishing the father's semen (yangjing) and mother's blood (pingxue) to produce bright, healthy babies (see Frank Dikötter's book Imperfect Conceptions). Many scientists and reformers of Republican China (1912-1949) were ardent Darwinians and Galtonians. They worried about racial extinction (miezhong) and "the science of deformed fetuses" (jitaixue), and saw eugenics as a way to restore China's rightful place as the world's leading civilization after a century of humiliation by European colonialism.