Are we too old for YAL?

Young adult literature is meant for teenagers around 13-19 years old.  If someone my age (30) wants to read something like The Fault In Our Stars do we have to read it behind closed doors so our peers won't see us?  Did you know that according to The Slate Book Review, 28% of YAL sales were purchased by 30-44 year old's?  This tells me that YAL is more popular than ever.  There are even sites for folks in their late twenties to mid-forties who prefer young adult novels over the prestigious award winning novels.

I began to wonder after reading those statistics why YAL has gained so much popularity since the 1990's?  Is it because many of the books are now better written and considered to be great pieces of literature and not just for Young Adult Fiction?  Or do we as adults, still relate to the content that is written.  In my opinion, I enjoy YAL because the content is so real.  I enjoy it because it talks about the taboo subjects that many writings only tip-toe around.  I once read a poem that was three pages long by Earnest Hemingway that I had no idea what it was about.  When we came together as a class to discuss this poem it ended up being about a woman who's lover was trying to convince her to get an abortion.  In my mind I think, "My goodness why didn't you just say that!"  Many scholars feel it takes out the imagination invoking literature to spell it out so bluntly.  I feel this is the exact example of why YAL is so much more popular today.

So is it true, do you need to be a certain age to publicly read YAL or is it acceptable to read it at any age?  If  you feel it is acceptable to read at any age, do you think you might be judged by a group of your peers when asked to describe what you're currently reading?  Are those opinions enough to make us change our minds on what we chose to read for leisure?