The number of people increasing does not preclude there being more fertility problems in general - in fact, given that we have more technology available to miti

The number of people increasing does not preclude there being more fertility problems in general - in fact, given that we have more technology available to mitigate fertility problems, but not to select against them in the next generation, I would even expect the percentage of people with fertility issues to be rising, absent any other pressure, since those people now have a higher likelihood of being able to reproduce.