There's no such thing as a single "gay gene" that drives a person's sexual behavior, concludes the largest genetic study ever conducted on the issue. Instead, a person's attraction to those of the same sex is shaped by a complex mix of genetic and environmental influences, similar to what's seen in most other human traits, researchers report. "This is a natural and normal part of variation in our species," said researcher Ben Neale, director of genetics with the Stanley Center for Psychiatric Research at the Broad Institute of MIT and Harvard. "That should also support the position that we shouldn't...