Gender in Canada

So, on the kind of random lark I have a tendency to end up on for no good reason, I found myself wondering what the legal definitions of male and female happened to be under Canadian law. Interestingly I couldn't find any definitions. All I could find was this passage in the Interpretation Act

33.  (1) Words importing female persons include male persons and corporations and words importing male persons include female persons and corporations.

...meaning by law that "male" and "female" are technically interchangeable and effectively meaningless. So, really, even before the Civil Marriage Act was changed from "the lawful union of a man and a woman to the exclusion of all others" to "the lawful union of two persons to the exclusion of all others" the legal meaning was the same (which, of course, is why it was a no-brainer to "change" it.)

It'd be interesting for someone to push this, for example, by pushing for having the gender on their ID changed without any gender reassignment surgery. Even better, I wonder if it would be possible to have the gender removed off your ID since it is legally irrelevant?