^ A couple of points to further support finfighter's argument:
1. As I said earlier, there's simply no way, physiologically, that finasteride (or any drug, really) could affect sperm quality within a day. There's a significant lag time between sperm creation and sperm release. The sperm you release tomorrow was created several weeks ago.
2. As crazy as it sounds, with the millions of men taking finasteride it's probably statistically likely that someone with a pre-existing or co-existing problem would discover they had symptoms around the same time they started taing the drug. It might sound "far out" to you, but I think if you did the maths on the number of people taking finasteride vs. the proportion of people (even young people) who have these problems, incidences like this would probably make sense. As finfighter said, correlation does not equal causation.
I'd further like to add that assuming, with 100% certainty, that finasteride is the root of Fanjeera's problem is actually likely to harm his chances of recovery. It might be finasteride, but it might not be. If it isn't, and Fanjeera chooses to dogmatically pursue this finasteride line of inquiry, then he could be achieving nothing while ignoring solutions right in front of him.
As far as I'm concerned, all options are still on the table right now, and I'm sure any qualified doctor would say the same thing.