Generally speaking, men find women with markers of fertility attractive. Overall, "developed" teens will be attractive, while "undeveloped" teens will not.

(Pedophiles are the rare breed who like the "undeveloped" teens).

Sexuality doesn't care about our laws, our ideas of morality or what we wish was or wasn't true. There are many occasions where women are attracted to serial killers and mass murderers (Ted Bundy), for example.

Of course, it goes without saying that grown men shouldn't flirt with teenage girls, and it should continue to be a major taboo. Consent must be given, and consent cannot be reliably given by those under 18.

There will always be men out there who are caught glancing at underaged girls. There will never be a time when this doesn't happen, because it's human biology. What we can hope for, is that our societies and our policing systems remain stable, and that boys and men continue to be educated, so that these glances stay glances, and don't turn into something worse.

Human nature is imperfect, and we have to make the best with what we've got.