In possession of what, and in which country? I assume you mean drugs of some sort. In the UK, the possession of class C cannabis is usually a warning and confiscation. Class B cannabis is much the same, as it has only recently changed to class B. Class A drugs will lead to confiscation, a … Read more

Yes. Even infrequent use of cocaine can cause a temporary 50% decrease in sperm. It is also known to decrease motility, or the 'quality' of sperm, ie. How easily it can swim towards the egg etc. And augments the penetrating quality of the sperm, so that they are less effective at fertilization.