To answer the above question let us consider seven rights and see if there are any differences between the two:
Heterosexual Homosexual
To freely practice their religion?: Yep Yes...
To freely express themselves? Yep Yes...
To assemble freely? Yep Yes
To hold to their beliefs, Yep Yes
opinions and ideas?
To vote: Yep (if the appropriate age) Yes (if the appropriate age)
To have a fair trial: Yep Yes
To marry (traditionally): Yep Yes...but...
But what?
But I can't marry who I want to!
That's true...however; neither can polygamists, people under age and people of the same family.
They may have grown up loving and wanting to marry more than one person, when they were below the proper age and in love with their own cousins. But we must realize that marriage is defined as one man and one women for a good reason. Even in classical Greece where homosexuality was widely accepted, but there is no known push to make up a new definition of marriage.
And remember: your free to have a ceremony (even in a church) and call it marriage. Your free to buy weeding rings and tell others your married.
The fact is, and I say this with no disrespect intended, that your rights aren't being violating because marriage between anyone and anyone is not, nor has it ever been a constitutional right.
I would also like to point out to you, that there is a sizable minority of homosexuals that agree with me and acknowledge that there is no real inequality.
In summery: The key issue here is not an existing inequality but if marriage should be redefined to include two consenting adults of the same gender, while at the same time excluding other people of different sexual orientations from yet another redefining of marriage because such people feel it's not fair for them.