>most of Europe and Japan have such low fertility
Their problem is not couples trying to conceive and failing, but people choosing not to have children.
Their problem is not couples trying to conceive and failing, but people choosing not to have children.
Which does not prevent it from being a problem. Government policy can change that. Not forcing teenagers to go $150.000 in debt and to have a career to repay that until they're in their 30s would be the bare minimum.
But a fertile body can influence the mind in all sorts of ways -- changing hormones can modify sexual desire, for example.