It was parchment, I believe, but I'm not 100% sure.
I believe the answer is: Developing nations
People in developing nations tend to have higher likelihood of being involved in sexual relationship without proper protection.
Many of individuals in developing nations also have very little awareness on the correlation between having more children with larger economic difficulties.
Both of these factors contributed to the increase of population.
I believe that it is the monroe Doctrine
"The few. The Proud. The Marines."
