YA Genre Boundaries

Now as you should know, my Erin the Fire Goddess series is in the YA genre. I chose this because it is written for my children. I want them to be able to learn from my books, and I want my books to help other children who face bullying.Now I am writing a new series and this is where my dilemma comes into play. My book will contain swear words. My EtFG series has contained basic swear words like shit, crap and bitch, but this new book will drop the F bomb and whilst I was having a conversation with my 13 year old daughter, I said I don't think it would be suited to YA genre because of this F bomb. To which Erin told me she has read many YA books that contain swear words and The Fault in Our Stars is supposed to be YA and that drops the F bomb. This got me thinking, what are the boundaries when it comes to YA as they seemed to be getting pushed. I personally believe no sex but even that seems to be getting pushed and has even opened up the whole NA genre.I want to know what are the limits? What words can't you say in YA genre. Not that I plan on using them I am just curious.I look at my work and think 'Would I let my teenager read this?'I definitely do not want my teenager reading about sex. As for swear words it is a difficult one, because even though my daughters do not swear they do hear it a lot. Mainly from me lol. They have become numbed to swear words. Their friends use swear words. So if you read YA, or write in it, I want your opinions please :)