I wouldn't know, I've never used them as such, only as birth controls secondary layer (because .. hormonal birth control isn't perfect, I know all to well!)
But then again I wouldn't know what current teenagers do - if that is a reason for them, well.. shitty reason but if it keeps them safe
my apologies to anyone I miss replying to, this went page 3 without realizing, thanks to all for your input, it is very welcome.