Here is the ultra-short summary for those who are not patient enough to listen:
"c. 1984, boys started coming into CS programs already knowing the basics. They knew the basics because they’d been coding already, sometimes for years. They’d been coding for years because the had a personal computer at home. They had a personal computer at home because it had been marketed to them. To boys. Pretty much exclusively.
Note the anecdote about cases where the computer was locked away in the brother’s room, even though the girl is the one who really wants to use it.
This is why it’s “interesting”, to use Hugh Everett’s term: We made it this way."