The teen birthrates you are citing do not distinguish between married teens and unmarried teens. I have asked several of you who keep posting those same statistics to come up with something showing that most of those teen births were outside of marriage. So far nobody has.
Yes, women got married much younger in the 40s and 50s than they do now, and many if not most were engaged not long out of highschool. But pregnancies almost all involved at least a ring and a date if not marriage, and/or a ring and a date were usually quickly produced if an unwanted pregnancy occurred.
The times were simply different then. And the result is that most kids had a mom and a dad at home with measurable social advantages involved in that.
As Williams said, is the high incidence of 'illegitimate' children, a large percentage of which are raised in poverty, are neglected, abused, or otherwise disadvantaged, and millions of abortions, preferable to those old fashioned taboos? And apart from those taboos, what would be a reasonable recommendation as a way to reduce the high number of 'illegitimate' pregnancies that result in so many societal problems that we have today?
Those must be really uncomfortable questions for some since nobody has presumed to touch them.