First of all, on the point of inquisitors not being able to procreate: Vin, despite being married for over a year, and half skaa (who are known to have more children), never gets pregnat. True, she is also half noble and Elend is full noble, and her body has suffered numerous traumas, so that could explain it as well...
Hemalurgy is all about reduction and breaking power into smaller and smaller pieces until it can all be destroyed (ie: killing several allomancers and feruchemists to put their power into an inquisitor), so, to me anyways, it could concievably make sense that it's touch renders you infertile.
Vin's mother, remember, had no spike, she was merely insane.
Just an idea.
Also, this may be a question fro Peter or Brandon, but something about hemalurgy has been bothering me.
The inquisitors gain the ability to store health in gold from their pewter spike, and as far as I know they have no gold spike (the power is unknown in the Ars Arcanum in book three anyways), so do they have gold metal minds like the Lord Ruler's atium ones that pierce their flesh so Vin couldn's see them? How were they storing gold?
Anyways, speaking of the Lord Ruler, we know that the atium bracelets were hemalurgically charged (In an annotation Brandon mentions that he is the product of all three magic systems, if I remember correctly), so what is the effect on him of having an atium hemalurgic piercing, besides having a metal mind to store his youth in that won't be stolen by allomancers?
Just a few questions... please, ponder away, I know I will be.
EDIT: I just realized that I have already asked this question with the inquisitors gold minds, however in my search I never discovered if it was answered. If it was, just point me in the basic direction or summarize the gist of it, and please forgive me my ignorance.