Famines are awful, but at least some scientific good can come out of them. They can be really informative natural experiments. Toward the end of the second world war, a German blockade cut food off from part of the Netherlands; thousands of people died. The Dutch Famine Birth Cohort Study follows about 1,000 people who were born at a particular hospital between November 1943 and February 1947. They’ve published dozens of papers about the long-term health of children who are born to extremely malnourished women.

Yesterday for ScienceNOW I wrote about a study on a different famine: the one that resulted from the Great Leap Forward in China. Tens of millions of people died when Mao’s campaign for quick industrialization went very, very wrong.

The paper I wrote about was looking at particular evolutionary theory that predicts the sex ratio of offspring should change in different conditions. So, if a mother is in good condition, she ought to have more male babies, and if she’s in poor condition, she ought to have more female babies. This has been shown many times for animals that aren’t humans, and scientists have looked for this before in the Dutch data but haven’t come up with conclusive results. Here’s my story.