I think it lacks a bit of context. See here: http://www.pbs.org/wgbh/evolution/library/01/6/l_016_08.html
http://www.theguardian.com/lifeandstyle/2013/sep/08/can-you-...
There was also a study that showed birth control to negatively affect a woman's ability to detect a genetic match by smell:
http://www.scientificamerican.com/article/birth-control-pill...