The impact of gays on teenagers is pretty much nil, except in some unusual circumstances. There are gay teens, but mostly, they associate with other gay teens. It is not like they give classes in Parental Disobedience ir How to Irritate Parents.
San Francisco is famous for Gays, cable cars and Rice-A-Roni, (the San Francisco treat). It is not noted for gang violence, every city has a bit of that.
Again, It seemed to me that the author of this Tiger Mom book did not tell everything, and would not have told everything even if that had been her goal. When it comes to dealing with your children, all sorts of things matter besides setting up rules of the house and such. Her goal was to sell lots of books, and to do that, she had to sound controversial, which is what gets you on Oprah and other talk shows where people go to hawk their books.
There is probably a lot of useful information in her book, and a lot of less than useful info as well. Her goal of getting her daughters into an Ivy League school was attained, but her much larger goal of selling a bazillion books, which will pay for the tuition and much, much more, was spectacularly attained. She is obviously a shrewd lady. Most Ivy League graduates probably do not make in twenty years what she earned from peddling that book.