This will be an ongoing work. Perhaps I need to take the Ethics course in philosophy.
The basis of my thesis is this:
A (male-only?) gay marriage family world inevitably expects some mothers to give up their babies.
A heterosexual marriage family world accepts but do not requires any mothers to give up their babies.
Any ethical system that cannot balance the utility of the society is worse than the systems that can balance such common utility better.
Therefore, a gay marriage worldview is worse than a heterosexual marriage worldview.
Apparently, a futuristic technology will be used by proponent of gay marriage to argue against this thesis in order to make a male-only gay marriage family be of no distinction from a female-only marriage family. Nonetheless, much could be argue from a maternal love perspective on labor, etc. This will go hand in hand with a paternal involvement as well. Debunking the use of futuristic technology, which is not even fully realized today.