It has just been announced that researchers at the University of Camford have discovered a correlation between unexplained infertility (i.e. where there is no apparent physical cause) and attention seeking.
A paper published today by Owen Leigh, Jo King and Soh Ree indicated that women who are have been diagnosed with unexplained infertility have a higher propensity to blog and less shame when talking about intimate procedures than the rest of the population.
The conclusion they have drawn is that infertiles actually don't want to become pregnant because once they do they will become more 'normal' and receive less sympathy and support from others. The suggestion is that unexplained infertility is a variation of Münchausen syndrome, that affects women at such a deep level that (without even realising it) they can prevent implantation of embryos.
You can read the full study here, and I strongly suggest you do.