I was thinking almost the same thing: people choosing not to reproduce selects for those who will reproduce, making the effort ultimately futile. But then cons

I was thinking almost the same thing: people choosing not to reproduce selects for those who will reproduce, making the effort ultimately futile. But then consider what happens when sexual reproducing species experience an extreme population dip: traits suddenly become much more variegated because now there is an overlap of recessive genotypes that used to be hidden. So maybe this won't happen?