alt Hacker NewsI think it's clear that the reduction in teen pregnancy is indeed a big contributor to the decreasing fertility rate. I would guess the reason this doesn't get brought up in discussions about how to _increase_ the fertility rate is that reversing the trend on teen pregnancy is just really not a palatable solution to many people. Although there are some, usually on the religious right, who advocate for banning contraception, teaching abstinence-only sex education, etc., which would most likely have the effect of reversing the teen pregnancy trend.
I think not talking about it skews the conversation towards incorrect remedies - the discourse is about what has changed about the economy, communities, family life, etc, that makes people want fewer kids and then trying to derive solutions from those things as the assumed problem. It makes too much of the discourse a question of “how do we go back to the previous conditions?”
If instead we say this is a biological imperative that we have interrupted and many people don’t rationally want children no matter how perfect those conditions are, then instead of looking back to previous states, we can ask what new conditions must occur to change this behavior.