Marriage between a man and a woman - Russel M. Nelson

"Marriage between a man and a woman is fundamental to the Lord’s doctrine and crucial to God’s eternal plan. Marriage between a man and a woman is God’s pattern for a fulness of life on earth and in heaven. God’s marriage pattern cannot be abused, misunderstood, or misconstrued. Not if you want true joy. God’s marriage pattern protects the sacred power of procreation and the joy of true marital intimacy. We know that Adam and Eve were married by God before they ever experienced the joy of uniting as husband and wife.

In our day civil governments have a vested interest in protecting marriage because strong families constitute the best way of providing for the health, education, welfare, and prosperity of rising generations. But civil governments are heavily influenced by social trends and secular philosophies as they write, rewrite, and enforce laws. Regardless of what civil legislation may be enacted, the doctrine of the Lord regarding marriage and morality cannot be changed. Remember: sin, even if legalized by man, is still sin in the eyes of God!"

Russell M. Nelson, Decisions for Eternity, 2013 Semiannual General Conference for The Church of Jesus Christ of Latter-day Saints

https://www.churchofjesuschrist.org/study/general-conference/2013/10/decisions-for-eternity?lang=eng