No. However, they only being allowed a "civil union", not being able to say that they're "married" set them apart from straight couples. That's discriminatory.
They could however say they were in a civil partnership. Marriage was clearly defined in law, as the union of one man and one woman. How long until they want the government to rule that heterosexual couples being able to have children is discriminatory?
I really dont mind one way or the other, I am just playing devil's advocate, however all the rights of marriage are encompassed in civil partnerships, except for the word "marriage".
There is, in my limited field of experience, no more under-represented group than straight white males.
We have the gay police association, gay and lesbian police association, black police association, association of women police officers, yet no organisation for the benefit of the group that are most prevalent in the force. I would put money on it being the same situation throughout every organisation.
Very often as one group recieves more rights it is at the expense of the erosion of the rights of other groups.