[necovek]

Another one of those fertility looks that doesn't even attempt to correct for the birth age move even though it brings it up at some point.

Basically, none of studies attempt to calculate fertility rates while we are in the middle of birthing age moving up. If looked simplistically, if people suddenly decided to have kids at 40 after they used to have them at 25, you get 15 years of significantly reduced fertility. It's not as clear cut today, but the figures are probably somewhere in between.