If You’re Born Gay, How Can A Homo Have a Straight Identical Twin?

In the nature v. nurture debate over what causes The Gay, nothing makes a better scientific experiment than identical twins. Born from the same set of cells and raised together by their parents, this set of twins — with one gay, one straight — has National Geographic concluding that sexuality can’t all be in the genes. Then, what else?

Blame the hypothalamus and testosterone, we’re told.