In this area there are civil partnerships but some friends who are gay say they have unequal rights and are being oppressed so are there different legal rights in these relationships?

Yes. Just to be absolutely clear, we're talking about civil marriage here, not marriage in the religious sense.

In some areas, "civil partnerships" are defined differently than civil "marriage.'' For example, a married person cannot be compelled to testify against their partner. A person in a civil partnership might not have that protection. Also, a marriage performed in one state is recognized in other states, but states usually do not recognize civil partnerships granted in other states. Further, the federal government does not recognize "civil partnerships" as equal to marriages.

Another problem is that no legislature can "bind" a future legislature. Even if a civil partnership is defined by one legislature as perfectly identical to a civil marriage, there is nothing to prevent a future legislature from changing the definition of civil partnership.