Friends can be called to testify against their friend in court. Friends can't always visity another friend in a hospital. Friends is not granted protections should they share property and break up.
A lebian relationshop cannot produce children.
It is not uncommon for one or both members of a lesbian couple to have sex with a man to have kids. I have heard of such situations, and they are raising the children together. I am interested in seeing how the kids turn out.
It can be argued that a childless couple ought not to have certain tax breaks.
But they are still married and enjoy certain legal protections that homosexuals do not.
The California legislature is presently considering legislation that would require the schools to teach tolerance for the homosexual lifestyle.
I am vocal against such things. I have been banned from DU, actually.
Well, the same limitations often apply to siblings and even to parents. Even without civil unions, legal instruments exist to establish common interests . Even when you sign a rental lease together you create legal obligations.
The lesbian relationship --as a sexual relationship-- does not produce children, whereas the most casual sexual encounter between a man and a woman can.