No baby booms or birth sex ratio changes following Fifty Shades of Grey in the United States

Introduction: The Fifty Shades of Grey (FSOG) trilogy were publicised by the media as inflaming increased coital activity, and that this would result a baby boom. Furthermore, increased coital activity skews the sex ratio at birth (M/T) toward male births. This study was carried out in order to ascertain whether there were any spikes in total births or in M/T in the United States (US) circa nine months following the FSOG books. Methods: Monthly male and female births for the US were obtained directly from the website of the Centre for Disease Control (01/2007-12/2015). Results: This study analysed 36,499,163 live births (M/T 0.5117, 95% CI 0.5116-0.5119). There are no discernible spikes in total births or M/T at annual level, or circa nine months after FSOG book releases i.e. 04/2012 and 01/2013. Discussion: The absence of spikes in births or M/T may have been due to exaggeration of the FSOG effect, it may only have provoked planned pregnancies, or modern contraception was sufficiently effective to prevent extra conceptions. The media build-up may also have stimulated a Hawthorne effect, with FSOG-affected individuals employing effective contraception. This study highlights the importance of measurement of cause and effect since anticipated results may not always ensue from events.