How would you explain the presence of many women in the early years of computer science, then?
Many occupations have undergone complete reversals in gender preference, so any statement about a bias should probably be read as a “current bias”. For example, secretaries and schoolteachers used to be fairly exclusively male professions. Now (at least in the US), it’s almost entirely reversed. And completely coincidentally I’m sure the status and relative wages of those occupations have dropped.