I've tried to Google this but haven't had much luck.
What can prevent conception in cases where both partners have no fertility issues? I just wondered why some people have to try for months before a positive test, and why there was no conception even if they DTD during the fertile window. It seems peculiar if they then manage to get a positive a few months later - what stops conception in those other months?
Soaps make conception seem to easy, so I would like to have realistic expectations before TTC.