Any Catholic who obtains a ‘gay marriage’ is automatically excommunicated for the sin of formal heresy, and must be denied holy Communion.
Canon 1364, n. 1: “an apostate from the faith, a heretic, or a schismatic incurs a latae sententiae excommunication.”
The claim that two persons of the same gender can have a true marriage of any kind (a natural marriage, or the Sacrament of Marriage) is a heresy. The ordinary and Universal Magisterium infallibly teaches that marriage is only between a man and a woman.
The claim that homosexual acts are moral, or that homosexual acts become moral by being done within a gay marriage, is a heresy. The ordinary and Universal Magisterium infallibly teaches that homosexual acts are intrinsically evil and always gravely immoral.
The procurement of a ‘gay marriage’ (a same-sex marriage) implies both of the above heretical claims. No Catholic adult could be ignorant of the fact that the Church condemns gay marriage and homosexual acts. Any Catholic who obtains a gay marriage is certainly obstinate in this heretical belief that two persons of the same gender can have a true type of marriage, and that homosexual acts are not intrinsically evil and always gravely immoral.
Marriage is generally a matter of public knowledge. Anyone who chooses marriage, makes a formal decision, a knowing choice. But the choice of a gay marriage is directly contrary to the infallible teachings of the Magisterium on marriage and sexual morality. Therefore, the procurement of a gay marriage constitutes a formal and public act by which the Catholic separates himself from the Church.
This automatic excommunication applies regardless of who performs the marriage ceremony, and regardless of whether or not the marriage is recognized the laws of the State.
Furthermore, any Catholic who is in a gay marriage is prohibited from receiving holy Communion, not only due to the sin of formal heresy, but also due to his or her obstinate perseverance in manifest grave sin.
Canon 915 “Those who have been excommunicated or interdicted after the imposition or declaration of the penalty and others obstinately persevering in manifest grave sin are not to be admitted to holy communion.”
Bishops, priests, deacons, and extraordinary ministers of holy Communion are obligated under Canon law to deny the Eucharist to any persons whom they know to be in a gay marriage, since such persons are persevering in manifest grave sin. The eternal moral law also obligates them to deny holy Communion to persons in a gay marriage, since such a reception would be a sacrilege and a grave scandal.
No one can legitimately claim to be a member of the Catholic Church, if he or she has chosen to marry a person of the same gender.
See also, my earlier post: All Are Not Welcome
Ronald L. Conte Jr.
Roman Catholic theologian and Bible translator