While homosexuality and gender dysphoria may have been occurring in nature during the pre-Decalog epoch, the human concept and understanding of sexuality was still evolving from instinctual animal behavior.
"Adam" decided that "this one shall be called 'woman,' for out of 'her man' she was been taken.""Eve" became the "mother of all the living." Sexuality, animal and human, was focused on procreation and survival. (Gn. 2:23, 3:14-20)
"The tradition of the Church has understood the sixth commandment as encompassing the whole of human sexuality." (Catechism of the Catholic Church #2336)
Church teaching has emphasized the indissoluble bond of one man and one woman, but the essence of the injunction against adultery still considers monogamy and heterosexuality as "property rights." The Church defines and confines the right to "suitable partnership" to man with one woman for life. Death extends the survivor's right to another "suitable partner."

cont'd...