This is Gary Becker, writing at the Becker-Posner blog.
I have argued several times previously that all “marriages” should be basically contractual arrangements between couples, whether heterosexual or homosexual. These couple-specific contracts would specify the duties of each member, including the conditions needed to terminate their arrangement, so that couples rather than laws and judges would determine the conditions under which they stay together or breakup. These contracts would be tailored to the special needs of each couple, and could even be made compulsory in order to take away any information revealed when a person asks his or her mate for a contract…
If such contracted civil unions became the norm, homosexual unions would not be any different than heterosexual unions. If civil unions obtained all the rights of marriage unions, then the issue of gay “marriage” would turn only on language, although it is emotionally charged language on both sides of the debate.
Posner’s view on homosexual marriage at the Becker-Posner blog.