05/13/2014 12:35 pm ET Updated May 13, 2014

Stress Gives You Daughters, Sons Make You Liberal

StA-gur Karlsson via Getty Images

The Northwestern University economist Charles Manksi calls it the “reflection problem”: How can we know if person A is affecting person B, or the reverse? Without being in each person’s head or observing every subtle non-verbal cue in their interactions, it’s impossible to know what’s causing what, who is the leader and who is the follower.

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