The issue focused on how many civil unions are available to same-sex couples.

The study was led by researchers at the University of California, San Francisco, and an academic research group at the University of California, Los Angeles.

The study was published in the April issue of the journal Science.

The study found that out of the 6,500 same-sex couples that were married in 2011, about 3,000 have been issued a civil union or same-sex marriage license.

