A 2006 study on fraternal birth order and homosexuality discovered that with each male child a woman has, the chance of her next son being gay increases. What followed was a problem neuroscientist Marc Breedlove called “a divide between the people doing the research and the people hearing about it.” He explains that while the corollary exists, the statistics are nearly impossible and it is far from the smoking gun of genetic sexual determinacy.

Watch this clip featuring NIH director Francis Collins for more on bioethics and “engineering” babies for desired traits.

More videos from this series: The Origins of Orientation

Recorded June 2011; Posted September 2011