A photography class is perceived as an easy and a 'cool' creative thing to do. The subject is seen as soft and the qualification is relatively worthless. It could be seen as shirking an academically rigorous subject for a less challenging subject that relies on practical bias.
Nearly 50% of UK coeducational schools have no female students taking A-level physics. Is physics seen as easy or cool? No. It's seen as difficult and geeky, which means a shortage of female pupils. It's not a good state of affairs. More girls doing physics and fewer doing photography is what we need.
Well...whatever the perception is, it's an academic subject at BA (Hons) level and above. Despite what some people think, a subject doesn't have to be scientific to be academic. Research is research after all.
While we clearly do get people who feel it's a walk in the park and an easy alternative to something more challenging ("it's just taking pictures" mentality), they're usually gone by the end of semester 1 as they quickly realise that's not the case and fail. They're mostly male however, and we get around 4 or 5 of those most years.
Is it more "vocational"? Well.. yes, understandably.. if you mean "doing stuff" = vocational. Does that make it easier? Nope. Different yes. The majority of male students just want to churn out technically driven, formulaic stuff to begin with, whereas the female students seem to be far more interested in innovating, and producing fresh new work by engaging in art based research. Male students find it harder to research, and simply don't see the value as much. Male students tend to not value photography as art as much... yet enrol on a Bachelor of Arts degree
.. they then spend 3 years complaining about the course rather than realising they're on the wrong course
They want a degree... but they want to gain one just by taking photos
This sadly, seems to be typical male behaviour. Female students embrace the research more, and have a clearer idea of what the course is for.
Is photography cool and creative? Absolutely. Is a creative subject easier? Of course not. It's no easier to be a good photographer than it is a good writer, or musician or actor or graphic designer. It's a creative endeavour, and the ones who succeed are the ones who work really hard and research and develop their work both academically and technically. Most blokes seem confused by what creativity is: Lately, they think it's taking pictures of Lego people and light painting (what's all that about?).
The fact is, there are less women photographers on sites like this, because it's all techy techy techy, all the time, and when anyone tries to discuss photography as anything else, you get shouted down as being "arty farty". Blokes love all that techy shizzle though... women just find it confusing it seems (not confused BY it... just it's importance as men perceive it).. they are just interested in the images, and in art. Women generally make better photographers as a result. Blokes are more likely to become technical photographers... commercial or industrial... far less likely to embrace the medium as an art form.
There are just as many famous women photographers as there are men.. probably more. It just seems to be that the male photographers seem to achieve more notoriety outside of academia/exhibition/fine art... partly because of the nerdy, technical and commercially acceptable nature of their work in what is essentially still a patriarchal society ... sadly.
Want it to change? Stop embedding gender roles into your children by the way you raise them. (shrug).
If you had argued that point 40+ yrs ago I might have agreed with you, but even 30 yrs ago, when I was at school in a northern town in a state comprehensive, girls were actively being encouraged to be more academic. The experience of my own kids, both girls, is that they have both been encouraged to do what they want to do - the engineering GCSE class at my daughters school was 50-50 boys and girls, sciences as popular with the girls as boys and more girls doing maths and business studies than boys. If that is society not encouraging girls, then not really sure what is. 
