I don't have data on this, but I'd imagine the popularity of computers in the home in the 1980s was outshining that of chemistry sets. In the NPR piece they talk about how computers were marketed to boys for playing games.
And chemistry is also taught in high schools, so both male and female students interested in it would've had some experience before attending college. The same is not true for computing.
A shift happened where computing was seen as something girls didn't do. If not marketing then what caused it? (IMO it started when computing became synonymous with math, if people thought girls couldn't do math then they also couldn't be good with computers).
You mean exactly like chemistry sets? Yet chemistry is the most equal major in terms of gender of graduates.
I like Planet Money, but this story is unconvincing.