For decades, the popular literature agrees with that the birth order affects people’s personalities and the popular books also invokes birth order for self-discovery, relationship tips, parenting guidance and so on. There is a factor of birth order may have influential effects on personality, the family size. The family size is related to ethnicity, education and wealth. More children frequently mean that parental resources, like money, time and attention, have to be spread thinly to each kid in the family. In addition, wealthier, better-educated parents typically have fewer children. The author took an example that, “21 of the first 23 astronauts into space were firstborns.” But the truth of that can be that most of the astronauts are from
