There's a guy out there really worried, not about same-sex marriage but same-sex procreation or conception.
http://www.eggandsperm.org/

"Equal protections, but no genetically engineered conceptions." In other words, we would federally recognize same-sex civil unions that do not grant conception rights, and prohibit all forms of conception that do not join a man and a woman's sperm and egg.

Note that this isn't just a matter of concern about near-term safety of genetic engineering or artificial gametes; he's into a total ban on anything like this. "All children should be created randomly equal."

On the other side is http://www.samesexprocreation.com/

Original source: http://metamagician3000.blogspot.com/2008/04/transhumanism-still-at-crossroads.html