This week, we’re looking at the science of sexual orientation, where debates over nature vs. nurture have influenced law, policy and equal rights. We’re joined by neuroscientist and writer Simon LeVay, to talk about his research on the topic, and his book Gay, Straight, and the Reason Why: The Science of Sexual Orientation. And on the podcast, astrophysicist Ethan Siegel returns to the show, to tell us about a new project using the information aggregation service TrapIt to improve learning in the classroom.