...so if it's targeted at children, 50% of children will take it up, thus the ratio of male:female programmers will remain the same, there'll just be more of them.
The book is aimed at girls. It would be nice to think that children were not conditioned by gender stereotypes at the age of 6/7, but unfortunately they are.
The current gender ratio is the result of decades of gender stereotyping that things like math and science and programming were "for boys".
I'm going to believe the author when she says that this is for children. I just don't buy the idea that boys can't enjoy stories with female leads. Look at Brave or The Hunger Games. My son loves those.