Gay, Straight, and the Reason Why: The Science of Sexual Orientation (2011; second edition 2016) is a book by the neuroscientist Simon LeVay and published by Oxford University Press.

The book received mainly positive reviews, praising it for LeVay's wide-ranging overview of scientific research on sexual orientation.

In 2012, it received the Bullough Book Award for the most distinguished book written for the professional sexological community published in a given year.