Teenage childbearing has been the subject of long-standing concern among the public and policy makers. Teenagers who give birth are much more likely to deliver a low birthweight or preterm infant than older women, and their babies are at elevated risk of dying in infancy. The annual public costs associated with teen childbearing have been estimated at $9.1 billion. The U.S. teen birth rate fell...

constantly very low there will eventually be a decrease in the population; if it is very high an increase will follow, other factors remaining unchanged. The threshold value of the birth rate constituting the border line between decline and increase of a population is 20, that is 20 newborns annually for every 1,000 inhabitants. As is shown in Fig. 1 there are several west and north European co...