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I have read many Shoujo stories and in all of them there are no sexual relationships before getting married. Is this something that is a must for all the main stream Shoujo? or it is acceptable for this genre to have sexual partners before getting married?
Thank you 🙂

If you do an advanced search with smut + shoujo, you get quite a few results, so there are shoujos with sex in them, if that's what you're looking for.

they aren't as common but there are some such as zig zag don

It changes with what's popular at the time. Currently "pure" romance is popular, but there have been many Shoujo with sex, and there have even been Shoujo with some really risque stuff!

yeah pure romance is very common nowaday, not sure if the shoujo manga magazine agenda has changed or a culture thing. Older shoujo from late 2000s and early 2010s were pretty relaxed with featuring character having sex (although the subject itself was considered a taboo even back then.)

There definitely are shoujo with sexual relationships, but it is taboo as shoujo is “maiden” manga, that is to say it is targeted to a young female audience. Generally elementary through middle to early highschool.

Shoujos take an innocent approach to romance since their target audience is mainly teenage girls. But there are exceptions.

..........Meh.