We have come to accept, however subconsciously, that scientists and engineers deal with hard things, like machines, test tubes and pipes. Solid manly things. Meanwhile, therapists, teachers and nurses deal with soft things, like people and feelings. Feminine, unquantifiable things. Over the decades, society has tended to place more value on professions involving hard skills - value that has seen high salaries and status for those who develop ‘hard’ skills.