I know of a family with 12+ girls and finally the last baby they finally got a boy. Don't know if they used any of the methods as this was a number of years ago probably before these books, but I am sure that they tried all different kinds of things. Tragically though, the boy died before all other siblings at 17 in a car accident.
If that is what you really, really want and would not want another girl. I would definitely talk to your Dr. you might want to consider IVF where they can determine the sex. I also do not know if they can do some sort of analysis on your husband's semen before you try again.