From Pope Paul VI:
At the present time there are those who, basing themselves on observations in the psychological order, have begun to judge indulgently, and even to excuse completely, homosexual relations between certain people. This they do in opposition to the constant teaching of the Magisterium and to the moral sense of the Christian people.
A distinction is drawn, and it seems with some reason, between homosexuals whose tendency comes from a false education, from a lack of normal sexual development, from habit, from bad example, or from other similar causes, and is transitory or at least not incurable; and homosexuals who are definitively such because of some kind of innate instinct or a pathological constitution judged to be incurable.
In regard to this second category of subjects, some people conclude that their tendency is so natural that it justifies in their case homosexual relations within a sincere communion of life and love analogous to marriage, in so far as such homosexuals feel incapable of enduring a solitary life.
In the pastoral field, these homosexuals must certainly be treated with understanding and sustained in the hope of overcoming their personal difficulties and their inability to fit into society. Their culpability will be judged with prudence. But no pastoral method can be employed which would give moral justification to these acts on the grounds that they would be consonant with the condition of such people. For according to the objective moral order, homosexual relations are acts which lack an essential and indispensable finality. In Sacred Scripture they are condemned as a serious depravity and even presented as the sad consequence of rejecting God. This judgment of Scripture does not of course permit us to conclude that all those who suffer from this anomaly are personally responsible for it, but it does attest to the fact that homosexual acts are intrinsically disordered and can in no case be approved of.