Birth rate
The region of Sub-Saharan Africa has the highest birth rate in the world. As of 2016, Niger, Mali, Uganda, Zambia, and Burundi have the highest birth rates in the world. This is part of the fertility-income paradox, as these countries are very poor, and it may seem counter-intuitive for families there to have so many children. The inverse relationship between income and fertility has been termed a "demographic-economic "paradox"" by the notion that greater means would enable the production of more offspring as suggested by the influential Thomas Malthus.
Sex education
A sex survey by the World Health Organization concerning the habits of European teenagers in 2006 revealed that German teenagers care about contraception. The birth rate among 15- to 19-year-olds was very low—only 11.7 per 1000 people, compared to 27.8 births per 1,000 people in the UK, and 39.0 births per 1,000 people in Bulgaria (which, incidentally, has the highest birth rate in Europe).