I think it lacks a bit of context. See here: http://www.pbs.org/wgbh/evolution/library/01/6/l_016_08.html

A little more context:

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...

I don't think it's lacking any context. Doesn't make the idea any less strange. : P