... think that the 'teen sections' are creepy?

A lot of people find young women to be quite beautiful. That interest is both cultural and biological. Combine that with a love of pregnancy, and you have... well, that section.

It may seem creepy because you've been conditioned to think it's creepy, but in reality it makes sense. Remember that in almost all cases, a pregnant teen has gone through puberty and is therefore a nubile woman. It is perfectly normal and healthy to be attracted to young, fertile females. That's part of what's helped our species propagate.

I believe it is important to emphasize the "they've obviously hit puberty" point because I think I see where you may be going with this, and I'd like to shoot that the hell down right away. Furthermore, those sections are specifically separated out from the others because they absolutely never feature nudity.

Thank you for your thoughtful response!