What other considerations about the morality of homogenital acts need to be made?
Besides appealing to Scripture and Tradition (constant Church teaching), the Catholic approach to morality also relies heavily on human reasoning. The argument from natural law is a prime example. Other instances are the study of the human sciences or attention to people's personal experiences.
But arguments from natural law are inconclusive, for the nature of human sexuality is debated. Procreation is certainly one aspect of sexuality. Yet the Catholic Church allows marriage between known sterile couples and sex between couples beyond child-bearing age. Moreover, Catholic teaching has recently emphasized the unitive aspect of sex — loving, caring, interpersonal sharing. Is the biological or the personal the key aspect of sex among human beings?
Similarly, the human sciences provide no universally accepted conclusion, but the majority opinion is that homosexuality is a natural variation, biologically based, fixed by early childhood, in no way pathological, and affecting about 6% of the population in virtually every known culture. (This 6% includes both the exclusively and the predominantly homosexual.) Likewise, while some may condemn practicing homosexuals as Godless and sinful, contemporary lesbian and gay Christians recognize their self-acceptance as a graced moment and report that, since coming out, they are happier, healthier, and closer to other people and to God.
Taken from Daniel A. Helminiak, FAQs: Catholicism, Homosexuality, and Dignity, written for DignityUSA, 1996, 2000.