I am an adult, and to my amazement, "Technology," a book published in 2012, had no female characters -- with one possible exception. Some examples: The author refers to the Movers-n-Shakers, Mega-Movers groups, the toilet and the telephone as "guys"; to gears & springs, microchips and rotors as "fellows"; to the radio, the digital camera, the 3-D printer and plastics as "dudes"; to steel as "the man of steel"; to the refrigerator as "the king of cool"; to the battery as a "portable prince"; and to the ion as "ion man." The possible exception: The author refers to the robot as "Cinderella," a character whose value as a female role model remains controversial. Ironically, some of the best characters in the book have no gender.
Unfortunately, the same blatant lack of female characters marks some the other otherwise highly interesting books in the Basher series, "Physics" among them. To be fair, I have not read them all. Nevertheless, I think that the publishers have no interest in inspiring young budding female scientists. I encourage Basher to publish a revised series that will address this problem.