Actualy, this would probably be very helpful.
With increasingly limited resources, overwhelming overcrowding and the strife caused between nations because of these difficulties, 50% of the worlds population suddenly deciding not to reproduce would be great for humanity.
We are not short on capable people at the moment and even if we were this population decrease would not drive up that shortage as there would be less people who require services from those capable people anyways. In otherwords what's so great about human societies is that they are capable of catering to both extremely large population bases and much smaller ones in the same degree.
Further more, human beings have a desire to mate and care for offspring. Even though those urges are somewhat reduced in certain individuals (making your scenario semi-realistic) letting said-individuals win over them, this is not the case for all human beings. And by the brilliance of natural selection, those individuals who do not have sufficiently strong urges to reproduce will be gradually (but rather quickly in this case) weeded out of the gene pool. What remains within the pool would be the genes which do promote breeding.
Thus this event would not only be wonderful for a world descending into choas at an alarmingly rapid rate because of overpopulation (perhaps even according humans enough surplus resources to kick start us up into a golden age) but it would also be over relatively fast.