1) Read: Mason, Karen O. 1997. "Explaining fertility transitions," Demography 34(4): 443-54 (JSTOR). Mention a few of the things demographers think they know and a few of the things they don't know about fertility transitions.
2) Read: Knodel, John, Napaporn Havanon, and Anthony Pramualratana. 1984. "Fertility transition in Thailand: a qualitative analysis," Population and Development Review 10(2): 297-328 (JSTOR). What are a few of the factors that explain the rapid fertility transition in this particular country?