Gay Marriage in Prisons?

A reader speculates:

It seems to me that one of these days, we're going to run into another collision of "rights", and it will be very interesting. 

Prisoners have the right to marry in every state. 

Gay marriage is legal in several states, and it won't be long until it's legal everywhere in the US. 

So what will happen when two cellmates apply for a marriage license?  On what basis will the prison be able to deny it? 

And couldn't this conceivably lead to bigger, stronger inmates forcing weaker ones into "marriages" against their will?  Will young white prisoners be the new "trophy wife"? 

Have you ever written about this?  I've looked around, and I can't find anything, except a brief NPR piece saying that no one has given it much thought, and no one knows how it will play out, but gay marriage in prison is inevitable.