It all works well...until something bad happens. Then the once-comforting belief now raises a bunch of unsettling questions. If the bad event was meant to happen for a reason, what was it? For instance, why do natural disasters happen, or do little children suffer painful and horrible illnesses? The answers are often not immediately apparent.
When experiencing infertility, the idea that it may have happened for some higher purpose can be troubling. I cannot count the number of times I have heard clients struggle with this issue, and they always seem to come up with the same answer: for some mysterious reasons, they are not meant to be parents. This worry usually only increases the painfulness of their situations. They cannot help but reflect that the situation seems so unfair. There are so many examples of people who are clearly problematic parents but who seem to have limitless fertility. They search their life for hidden sins or exaggerate the importance of minor flaws, all in the service of discovering the "reason" their infertility has happened to them. Eventually, they come up with quite complicated, convoluted theories about their alleged unfitness to parent, almost all of which appear, to me at least, to be patently untrue.
In addition, those struggling with infertility often must also contend with the comments others make about how "when it's meant to happen it will", or how they should just relax and trust God or fate or whoever or whatever is supposedly in charge of these things. These comments often add to their worries about themselves as potentially unfit parents. Further, they now are concerned that the feelings of sadness, impatience, and anger they feel aren't normal--shouldn't they just "relax and let it happen"?
Although I would never claim to have the answers as to whether or not things happen for a reason, I do know this: I have myself been infertile for a long time, and I have talked to many people who have also struggled with infertility, as well as people who have suffered many other types of terrible losses. I myself have never been able to piece together a convincing reason that all of these bad things happened, either in the individual cases, or collectively. Rather, I think that it is more likely that there is a lot of random chance at play. Out of 100 couples, 8 of them will experience infertility for separate and different reasons. I happened to be in the part of the population that is infertile, for various medical reasons, some currently diagnosable and some not. If you are dealing with infertility right now, I think the same is probably true in your case. I doubt it has much to do with your personality, your goodness as a human being, or your fitness to be a parent.
The downside to not believing that everything happens for a reason is that it is, from an an emotional perspective, scarier to live in a world where events are affected by random chance. After all, that means that all bets are off; anything could and might happen, even if it is not particularly likely. On the other hand, it does save us from creating explanations of difficult or tragic events that cause us to feel terrible about ourselves, and that seem unlikely to be true. Plus, it makes us appreciate our good fortune when it occurs--it isn't just "meant to be". It is the result of some good luck and our hard work combined. This can help build self-esteem. Further, we can be more empathetic with others who have experienced misfortune as well, for we understand what it feels like to end up on the wrong side of random chance.