I believe one of the justices responded by asking if he felt that heterosexual couples that do not pro-create should be precluded from marriage.
They also had a problem with the old argument that same sex couples can get married, they just have to marry someone of the opposite sex.
Of course, the argument of same-sex marriage having a detrimental affect on 'traditional heterosexual marriage' was met with discussion of divorce statistics.
The opposition certainly didn't seem to make any logical arguments, not that they ever do! But it will come down to whether or not the justices want to make any ruling on this or shoot it back down to the legislators and possibly another public vote.
"Struggle is a never ending process. Freedom is never really won, you earn it and win it in every generation."
Coretta Scott King