Can an Employer Fire an Employee for "being too sexy"?

Did you catch the story that was all over the American news this weekend about the New York banker who has sued Citibank for dismissing her for “being too sexy”?  Here is a New York Times op-ed on the story, and here is the original Village Voice article that broke the story. The woman (Lorenzana) is milking her 10 minutes of fame for all it’s worth, appearing on all the New York morning shows.  She alleges that she was told she could not dress like the other women in the office because, due to her body shape, she was too distracting. The employer claims she was fired for poor performance, but she says it was because she would not accept the special clothing rule for her only.   Let’s assume her allegations are provable.   Now think about how this case would play out in Canada.

Can a woman sue her employer for dismissing her for “being too sexy”?

Well, start with the common law.  Under the common law, a nonunion employer doesn’t need a reason to dismiss someone, as long as it gives the employee either the written notice required in the contract, or if there is no written term, “reasonable notice”, as defined by a set of criteria judges have made up over the years.  A unionized employer would need to have “just cause” to dismiss the employee, and “being too sexy” would almost certainly not meet that standard.  So, a “too sexy” unionized employee would probably get reinstated, whereas a “too sexy” nonunion employee would likely lose her job, but be entitled to some period of notice.
But then there is also the issue of the Human Rights Code.  Is discriminating against a female employee for “being too sexy” discrimination or harassment on the basis of “sex”?  That’s not as obvious a question as it might seem.   Discrimination on the basis of physical appearance is not prohibited by the Code, unless physical appearance is a proxy for a prohibited ground.  For example, if an employer fires me because it thinks I’m “ugly”,  do I have a human rights complaint?  The answer is, only if by ugly they mean that they don’t like my skin colour, or my ethnicity, or my disability, or they think all men are ugly, for example, so that it is really sex discrimination.  But if the employer just thinks I’m unattractive, but it has nothing to do with a prohibited ground, then I don’t have a human rights case.
So, what about a woman who says she is fired for being “too beautiful”?  The employer is not against women in general–it has lots of female employees–and no one is alleging that race, age, disability, or any other prohibited ground was involved.   Her claim would be that being too beautiful is sex discrimination.  Is it discrimination on the basis of “physical appearance” (not prohibited by the Code), or discrimination on the basis of “sex”, which is prohibited?
According to the allegations,  the employer told Lorenzana that she alone (not the other female employees) needed to wear loser fitting clothes because when she wore what other women wore, she was too distracting to her male colleagues.   That seems unfair to Lorenzana, but is it discrimination on the basis of sex?
One analogy might be the Brooks v. Safeway case, in which the Supreme Court ruled that discrimination against a pregnant woman is discrimination on the basis of “sex”, even though pregnancy is a state that only a small percentage of women are in at any given moment.  Since only women can be pregnant, a rule adversely impacting pregnant persons is a rule that adversely impacts only women.
See also Janzen v. Platy Enterprises, where the Supreme Court ruled that sexually based harassment is included within the meaning of “sex discrimination” in human rights statutes.  It was only because the employee was a women that she was subjected to the harassment.  The court said that “sexual attractiveness” cannot be divorced from gender.
Considering these cases, do you think that a women fired for being “too sexy” would have a strong sex discrimination complaint against the employer in Canada?