There is a good chance it won't happen for Judge Roberts is a legal minimalist and he hates sweep judicial decisions that affect large theory of law. The reason why he hates them for he is a judicial conservative in his own way
1) Large sweeping changes of law can have unintended consequences
2) Furthermore it makes the courts look less like umpires and more like lawmakers. Perception is a big deal for if courts are perceived as lawmakers the courts will become greater politicalized.

Most likely John Roberts would rather take up a DOMA case for he can make the decision much more narrow.

---------------------------------------------

Now it isn't just up to John Roberts for it only needs 4 justices to grant a writ of certiorari. The 4 liberals on the court though won't grant a writ though unless they are sure they will have 5 justices on their side so that way they won't create bad precedent by losing the case.