The paper also estimates the number of children saved at 57 per year, so the safety impact is even lower

Let's call it 80 and you get a rate of 1:100 children saved per children not conceived. What would be a reasonable rate in your mind?

Car seat design has improved you can readily fit three car seats in most vehicles these days

This is a weirdly funny thread. How many theoretical children would you trade for 1 real child? All over a car seat that perhaps prevented 4,000 additional births a year?