It wasn't translated so it's not in my report, but a number of studies have shown that different variables play a role. There are individual variables. There's your character. Maybe you play with Meccano sets or maybe you play with Barbie dolls. It depends on the environment you grow up in. Parents are a very big influence. Parents, the research shows, are much more of an influence on girls than they are on boys. Peers are more likely to be an influence on boys.
One of the things that can have an impact and that could have had an impact on someone like me, for example, coming as I did from a single-mother secretary family, is what we call a transforming experience. So a teacher, a guidance counsellor, or a family friend who introduced me to the notion.... Girls are more likely to become engineers if someone in their family has been an engineer. Girls are more likely to be police officers if someone in their family has been a police officer.