UK: Why do we worry that few girls take physics, but not that boys make up just 29% of English A-level students?

Article here. Excerpt:

'A few years ago, I walked into a university to find several posters of my face. That was disconcerting enough. But it was advertising a graduate scheme for a science teacher – and I am a citizenship teacher. I made inquiries, and was told a focus group had suggested a female teacher was needed for the campaign to "break stereotypes" about scientists. The organiser quipped: "I think your being blonde was a bonus."
...
Like the university tutors who thought sticking a blonde woman on a science poster would somehow resolve gender disparities, Truss's main solution to the science gap appears to be gutsy role-modelling. In a recent speech to Google, Truss said: "It's up to all of us to encourage girls and say, you are just as good as the boys, you can do it."

But why are girls the ones constantly pathologised? This narrative makes out that girls are afraid to study the big scary sciences: but another way of thinking about it is that boys are the odd ones – crowding as they do into just a few subjects. They take up 60% or more of places in just five subjects, and two of these – maths and physics – are particularly dominated by boys, with the subjects accounting for one in five of all A-level examinations taken by boys.
...
Looked at in this way, the question we need to answer is less "Why do so few girls choose physics?" and more "Why do so many boys only choose physics and maths-related subjects?" After all, if they spread themselves out across all other subjects, girls would no longer be regularly outnumbered in physics.

Sadly, few politicians question gender disparities in other subjects. The schools minister has referred on several occasions to the fact that 40% of students who take maths A-level are female. She is at pains to point out how disastrous this is. Yet male participation rates in psychology, sociology, and religious studies are regularly well below 40% and no one bats an eyelid. One might argue that these are not "core" subjects. But boys only make up 29% of English A-level students – why isn't that deemed a "problem"? Apparently only girls deserve that label.'