In a Mar. 15, 2021 document from the Holy See Press Office, the Vatican confirmed the Catholic Church would not bless same-sex marriages:
“TO THE QUESTION PROPOSED:
Does the Church have the power to give the blessing to unions of persons of the same sex?
In some ecclesial contexts, plans and proposals for blessings of unions of persons of the same sex are being advanced. Such projects are not infrequently motivated by a sincere desire to welcome and accompany homosexual persons, to whom are proposed paths of growth in faith, ‘so that those who manifest a homosexual orientation can receive the assistance they need to understand and fully carry out God’s will in their lives’
…in order to conform with the nature of sacramentals, when a blessing is invoked on particular human relationships, in addition to the right intention of those who participate, it is necessary that what is blessed be objectively and positively ordered to receive and express grace, according to the designs of God inscribed in creation, and fully revealed by Christ the Lord. Therefore, only those realities which are in themselves ordered to serve those ends are congruent with the essence of the blessing imparted by the Church.
For this reason, it is not licit to impart a blessing on relationships, or partnerships, even stable, that involve sexual activity outside of marriage (i.e., outside the indissoluble union of a man and a woman open in itself to the transmission of life), as is the case of the unions between persons of the same sex. The presence in such relationships of positive elements, which are in themselves to be valued and appreciated, cannot justify these relationships and render them legitimate objects of an ecclesial blessing, since the positive elements exist within the context of a union not ordered to the Creator’s plan.
Furthermore, since blessings on persons are in relationship with the sacraments, the blessing of homosexual unions cannot be considered licit. This is because they would constitute a certain imitation or analogue of the nuptial blessing invoked on the man and woman united in the sacrament of Matrimony, while in fact ‘there are absolutely no grounds for considering homosexual unions to be in any way similar or even remotely analogous to God’s plan for marriage and family’.
The declaration of the unlawfulness of blessings of unions between persons of the same sex is not therefore, and is not intended to be, a form of unjust discrimination, but rather a reminder of the truth of the liturgical rite and of the very nature of the sacramentals, as the Church understands them.”