I was interested in the relationship between how many children women have and life expectancy. Which should be the dependent and independent variable is not obvious. I focused on Costa Rica, a country of personal interest. The mean number of children per woman has decreased steadily over the last few decades, but exhibits declines and reversals at earlier points (how much of these reversals is the result of data interpolations vs. actual reversals is a question to consider). Life expectancy increases with decreasing fertility.
link to graph here www.bit.ly/zJaYF9