Imagine, if you will a large endless expanse. Clear skies above, but as you look to the floor you realize it's made of people. Compacted like tetris pieces, as far as the eye can see. You're standing there, presumably atop some people right then and there. What do you do? Do you walk forward? You'll step on the bodies; the people. Do you stand still? Won't that invalidate your life? Aren't you allowed to live?
Making that decision is trying hard enough. We all had to do it, and luckily, we did it at an age we can no longer remember; right when we were born. We decided to venture forth and try. You tried hard enough because you tried, period. That is enough.
Historically, there has been a lot of pressure to reproduce, but in the modern era this doesn't always make as much sense. I wish there was more research to clarify this phenomena.
We'd potentially be avoiding a lot of grief and angst during young adulthood for those who choose not to be parents if they more clearly understood why it doesn't "feel right". That grief and angst from choosing "wrong" potentially translates to cases of mental illnesses in the children at best and domestic abuse at worst. Even when couples choose not to have children, they can still be very unhappy. It's as much a matter of social justice as it is health.