Genesis 2:24 Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh.
The first issue has to do with the marriage institution that was given to the human family, directly by God Himself. When God pronounced Adam and Eve as being married, He did set in stone the format of one man and his female wife, as the gold standard for all future generations to follow.
Genesis 2:21 And the Lord God caused a deep sleep to fall upon Adam, and he slept: and he took one of his ribs, and closed up the flesh instead thereof; 22 And the rib, which the Lord God had taken from man, made he a woman, and brought her unto the man. 23 And Adam said, This is now bone of my bones, and flesh of my flesh: she shall be called Woman, because she was taken out of Man.
And since that time, God has not changed His mind one iota. God has not taken into consideration any social norms, or what popular majorities think, say, or legislate on the matter. Cultural biases and one’s personal preferences and choices do not move God to change His mind on certain issues, for which He has already stated what is the right thing to do.
Matthew 19: 4 And he answered and said unto them, Have you not read, that he which made them at the beginning made them male and female, 5 And said, For this cause shall a man leave father and mother, and shall cleave to his wife: and they twain shall be one flesh?
May The Lord add His blessing to the study of His word. God bless!