In the wake of New York redefining marriage, Archbishop Dolan of New York issues a decree to Catholics in his archdiocese:

For millennia, civil authority recognized the true nature of marriage. The marital union between one man and one woman was universally accepted by civil law as a constitutive element of human society, which is vital to the human family and to the continuation of the human race. In a reversal of this tradition, the New York State Legislature recently enacted a law that recognizes same-sex unions as marriages in the State of New York. This law is irreconcilable with the nature and the definition of marriage as established by Divine Law.

He goes on to explain what Catholic policy is vis-a-vis these same-sex ceremonies (our paraphrasing):

a) no priests, deacons or laypeople employed by the archdiocese may participate in or help facilitate a same-sex ceremony
b) no Catholic property can be used to help facilitate a same-sex ceremony
c) no Catholic liturgical items may be used to help facilitate a same-sex ceremony
d) failure to follow this policy may result in church law penalties