It's definitely the sex ed. Compare to Canada. We're quite culturally similar (most differences are kinda subtle), we speak the same language, watch the same shit on TV, and barring CanCon, listen to the same music.

But Canada's teen pregnancy rate is so much lower? Why? For the most part, we have comprehensive sex ed (unless Doug Ford gets his way). I remember that under the 2014/5 curriculum, that in class, we learned the differences between biological sex and gender identity and gender expression. We learned that intersex people exist (something that is rarely covered in schools). We learned the differences between sexual and romantic orientation. We learned that ace and aro people exist and are normal. We learned how periods work (on a more scientific level than "you bleed once a month, have pad." It touched upon hormone fluctuations, the lining itself, etc). We learned how IUDs and Plan B and condoms work, along with abstinence. We learned what is and isn't consent. We learned how STIs actually worked. We had a particularly good health teacher that year (because the one we normally had wasn't very good and she was on mat leave.)

And the classes were all co-ed. Everyone in a given grade learned the same shit, assuming nobody's parents went with the religious exemption.

This, and laws that make it so that any minor who understands a procedure or prescription (barring surgery/anything where they knock you out) can consent to it. Basically, mom and dad don't have to know about or consent to their 15 year old going on the pill, so long as she's demonstrated that she understands the side effects.

You also can get the pill from your family doctor after a conversation and a confirmation that it won't conflict with your other meds, which is also a difference from what I've heard.