So I recently found this on the Parliament of Canada website:
While there is no Standing Order setting down a dress code for Members participating in debate,  Speakers have ruled that to be recognized to speak in debate, on points of order or during Question Period, tradition and practice require all Members, male or female, to dress in contemporary business attire.  The contemporary practice and unwritten rule require, therefore, that male Members wear a jacket, shirt and tie as standard dress. Clerical collars have been allowed, although ascots and turtlenecks have been ruled inappropriate for male Members participating in debate.  The Chair has even stated that wearing a kilt is permissible on certain occasions (for example, Robert Burns Day).  Members of the House who are in the armed forces have been permitted to wear their uniforms in the House. 
What could possibly justify this Speakers’ rule?
Could it be that our Members of Parliament can’t dress themselves? The people we’ve voted into positions of power? Doubtful. They’re adults. Many of them even have a university degree. (Okay, I know …)
Could it be somebody in a higher position of power is prioritizing appearance over reality? What you look like is more important than what you are like. That bodes well for, well, the world.
Could it be someone in a higher position of power is making a series of non sequiturs from clothing to behaviour and character? If you wear a business suit, you must be honest, hard-working, mature – respectable. Say what?
It is certainly that someone in a higher position of power is appealing to tradition and practice. Philosophers rightly consider that fallacious reasoning. Just because we’ve always done it that way, just because we do it that way, doesn’t mean we should.
And the other thing to note? There’s no mention of what exactly female members must wear. Because there’s no standard business attire for women? No, that can’t be right. To judge by the Speakers’ own criteria, tradition and practice, it is standard for women to wear shoes with high heels (that will be uncomfortable for standing, difficult for walking, and eventually cause postural pain), to wear a skirt or dress (that will ensure their legs are showing, because – men want to see women’s legs at all times?), and at the very least to not wear a jacket, shirt, and tie – because we MUST MUST MUST enforce the gender norms. Our patriarchy depends on it.
(Oh, one other thing to note: “..male Members wear a jacket, shirt and tie” – what, no trousers?)