for example:
Ann can marry Bob
but Charlie cannot marry Bob, solely because he is male.
so Charlie does not have the same rights as Ann and is
being discriminated against because he is not a woman.It isn't necessary to make this argument in Canada, however, because there is a constitutional protection against legislation/policy that discriminates on the basis of
sexual orientation.
The Canadian Charter of Rights and Freedoms (which is Part I of the Constitution Act, 1982, Canada's modern constitution) says:
http://laws.justice.gc.ca/en/charter/(Emphasis added to indicate where the Charter expands on traditional "equality
before the law" and "equal
protection of the law")
Equality Rights
Equality before and under law and equal protection and benefit of law
15. (1) Every individual is equal before and under the law and has the right to the equal protection and equal benefit of the law without discrimination and, in particular, without discrimination based on race, national or ethnic origin, colour, religion, sex, age or mental or physical disability.
That provision became effective in 1985. All governments in Canada are subject to the Charter, and legislation that is incompatible with the Charter is invalid -- unless the govt in question specifically enacts that a particular piece of legislation applies
notwithstanding equality rights, e.g. A mere desire to deny equal protection and benefit to gay men and lesbians would be seen by a majority of Canadians as a pretty crappy reason to exercise that exceptional power, although it's something that the right wing has bandied about.
Not long after the Charter's equality rights became effective, the Supreme Court held that the prohibited grounds of discrimination listed in s. 15 are
not exhaustive, i.e. they are examples of prohibited grounds, but others may exist.
In 1998, the SCC held that a provincial government's human rights code (governing discriminatory practices in the private sector) that prohibited discrimination on the ground of race, sex, religion, etc., and
did not prohibit discrimination on the ground of sexual orientation, was unconstitutional -- because it violated the rights of gay men and lesbians to the equal protection and benefit of the law.
http://www.lexum.umontreal.ca/csc-scc/en/pub/1998/vol1/html/1998scr1_0493.html(italicized emphasis mine)
69. It is easy to say that everyone who is just like "us" is entitled to equality. Everyone finds it more difficult to say that those who are "different" from us in some way should have the same equality rights that we enjoy. Yet so soon as we say any enumerated or analogous group is less deserving and unworthy of equal protection and benefit of the law all minorities and all of Canadian society are demeaned. It is so deceptively simple and so devastatingly injurious to say that those who are handicapped or of a different race, or religion, or colour or sexual orientation are less worthy. Yet, if any enumerated or analogous group is denied the equality provided by s. 15 then the equality of every other minority group is threatened. That equality is guaranteed by our constitution. If equality rights for minorities had been recognized, the all too frequent tragedies of history might have been avoided. It can never be forgotten that discrimination is the antithesis of equality and that it is the recognition of equality which will foster the dignity of every individual.
... 72. As stated by Sopinka J. in Eaton v. Brant County Board of Education, <1997> 1 S.C.R. 241, at paras. 66-67:
... the purpose of s. 15(1) of the Charter is not only to prevent discrimination by the attribution of stereotypical characteristics to individuals, but also to ameliorate the position of groups within Canadian society who have suffered disadvantage by exclusion from mainstream society as has been the case with disabled persons.
The principal object of certain of the prohibited grounds is the elimination of discrimination by the attribution of untrue characteristics based on stereotypical attitudes relating to immutable conditions such as race or sex. ... The other equally important objective seeks to take into account the true characteristics of this group which act as headwinds to the enjoyment of society's benefits and to accommodate them.
... 77. The respondents concede that if homosexuals were excluded altogether from the protection of the IRPA in the sense that they were not protected from discrimination on any grounds, this would be discriminatory. Clearly that would be discrimination of the most egregious kind. It is true that gay and lesbian individuals are not entirely excluded from the protection of the IRPA. They can claim protection on some grounds. Yet that certainly does not mean that there is no discrimination present. For example, the fact that a lesbian and a heterosexual woman are both entitled to bring a complaint of discrimination on the basis of gender does not mean that they have equal protection under the Act. Lesbian and gay individuals are still denied protection under the ground that may be the most significant for them, discrimination on the basis of sexual orientation.
In the US, equal-protection analysis is different, since the US constitution does not contain the kinds of equality rights present in the Cdn constitution. The US courts have developed a method of scrutinizing legislation that is challenged on the basis of denial of equal protection that resembles the method used in Canada in many ways. But the US courts don't start from the blanket guarantee of equality present in Canada, and they prioritize "suspect classifications" (race, sex, etc.) as
a priori more or less important -- whereas Cdn courts examine legislation on a case-by-case basis to determine whether they deny equality, without a predetermined hierarchy of importance based on the ground on which equality is denied.
A useful guide to the process in the US:
http://www.law.umkc.edu/faculty/projects/ftrials/conlaw/epcscrutiny.htm"Levels of scrutiny under the equal protection clause" (of the US constitution)