I'm boggled enough to reply.
Sexual promiscuity is at an all time high. With the rise in popular media (cheaper TVs, cheaper internet, cheaper computers, phones, tablets, etc.) the world is being fed tonnes of sex propaganda.
Is sexual promiscuity at an all time high or has the rise in the use of media that you refer to resulted in publicitiy of sexual promiscuity being at an all time high?
Boys and girls are becoming sexually active at unprecedented ages.
Rubbish. There's a lot of precedent throughout history. It wasn't much over 100 years ago that the age of consent in the UK was raised to 16. It used to be legal to marry at 12 and that wasn't an oddity of this country. Whether it's right is a different matter, but it's very obviously not unprecedented.
Lets face it, you rarely, if ever, see "celebrity idols" fully or decently clothed these days.
For example (among many), on several occasions I have witnessed girls who I thought had completely forgotten to wear a skirt over their tights (these weren't jeggings).
Clothing standards have frequently been changed by some people pushing the limits of what is allowed. There isn't any objective standard of restraint. It's all subjective. For example, in later republican and imperial Rome it would have been shocking for a woman to wear a toga. The only women who wore togas were prostitutes.
Now this is where Justin Bieber comes in. These young girls are growing up believing Justin Bieber is a man.
Which he is. Well, I assume he is. I suppose it's possible that there's a bizarre conspiracy and they're actually a woman in disguise...but why would that happen? If a media company wanted an androgynous male youth as a marketing device (as they obviously did) then it would be far easier for them to hire an androgynous male youth rather than hire a woman and maintain a conspiracy.
When they become sexually active, the age of which is also getting younger and younger, they will naturally limit themselves to skinny-jeans wearing borderline homosexuals. Gone will be the days when women were attracted to manly-men.
So you're talking about gender, not sex, and you just don't understand the difference between sex and gender and you might not understand that sexual orientation is something different too.
There are issues regarding changes in sexism and the resulting changes in gender and how that has stigmatised both masculinity and maleness, but I don't think that's what you're talking about.
This brings me onto the topic of homosexuality. (I stress that I'm not judging homosexuality in any way, merely discussing the evolutionary impact of increasing homosexuality.)
The media is full of homosexuality. Gok Wan, Alan Carr, David Walliams et al, are filling the media with gayness. These days, heterosexuality is being phased out as a necessity of life and homosexuality is being influx as a choice of life. Gone are the days when adolescents having their first sexual attractions initially tried to like girls, and only turned gay if it didn't work. Now it's a choice and they're both normal, a kid growing up will think "ah I remember that guy saying liking boys is normal" and will initially start having homosex with his buddies rather than even trying to get a girlfriend for heterosex.
I'm not saying decent women and straight men will be wiped out in a months time; I'm simply predicting that they will become scarce, like ancient tribes are today, in 100 to 5,000 years time.
Eh?
An increase in the number of neutral references to homosexuality in the media isn't an increase in the proportion of people who are homosexual.
A reduction in the proportion of homosexual people who initially try heterosexuality in order to conform isn't an increase in the proportion of people who are homosexual.
Even if there has been an increase in homosexuality in humanity (and there doesn't seem to be any evidence that there has been), it would still be...not supported by evidence and reasoning...to conclude that a very large majority of men will be homosexual in the relatively near future.
You also seem to have somehow managed to overlook the fact that about 50% of adolescents are female.