Hard cases make bad law, and bad theology too.
(BTW, once they start talking they are no longer "infants". Latin infans = incapable of speech.)
Of course. However the church of England merely recognized _celebate partnerships_ and did not call these "marriage". Clergy (or others) living in celebacy has a two thousand year tradition in nunneries, monasteries, as well as ordinary lay communities.
The problem is not with folks (gay or otherwise) who wish to support each other in celebacy, but with those (both gay and heterosexual) who wish sexual freedom without consequences.
The "bad theology" is the first one, which says that marriage is simply a political or social construct that gives "rights" to two folks (a man and woman currently) who wish to live together. It is not. Marriage is the foundation of human society, results in an indisoluable and eternal communion of two people and is integrally linked to the genesis of children (who are also indissoluably, and eternally in communion with their progenitors).
This initial decoupling of marriage from its theological roots initially manifested in the use of birth control, and later was extended to divorce and abortion, and this (heterosexual) perversion was then coopted by gays, (and may well be coopted in the future by polygamists, the incestuous or whatever.
However, the way to deal with this is not by saying that the unmarried should live alone and away from family, and should not be permitted to care for the ill or for orphans, but to agree that marriage is in fact fundamentally linked to procreation, and to make divorce more difficult.
Frankly, my solution would be to limit marriage (and any benefits thereof) to the first marriage between a previously unmarried man and unmarried woman, and to refuse to recognize later "marriages" after divorce. Oddly enough, this is the position of the Catholic church.