As recorded in the Book of Genesis and the Books of Moses and Abraham in the Pearl of Great Price, the Lord created the world, and the plants and animals, but he didn’t just create them and move on. They were all beings with intelligence; he spoke to them.
“…God blessed them, saying, Be fruitful, and multiply, and fill the waters in the seas, and let fowl multiply in the earth…” (Genesis 1:22; Moses 2:22; also Abraham 4:22)
So these brand-new intelligent beings were given a commandment from their creator, and that commandment was…have sex. Since being fruitful and multiplying cannot occur without sex, the commandment was, logically, to work to complete a full sexual cycle of having children, offspring being the “fruit” of a sexual pairing that tend to “multiply” the more often the cycle is completed.
Although this same direct commandment is not recorded in scripture to the land animals, reason necessitates the idea that they, too, received this commandment from their creator. President Hinckley stated,
“Then followed the creation of animal life in the sea and upon the land. He commanded them together to multiply and replenish the earth.” (Hinckley, Gordon B. “Daughters of God”, Ensign. Nov 1991. Italics added.)
So once the animals were created and given their instructions,
“God created man in his own image…and God blessed them, and God said unto them, Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth.” (Genesis 1:27; Abraham 4:26)
The first commandment to the first man and woman on the earth was the same; to multiply and replenish the earth. In other words, they were informed of their duty to have sex and procreate. It was the same commandment given to the animals, but with additional responsibilities and duties, for two reasons.
What was the first reason? Adam was on a different plane than animals, and God expected more of him. He was created in the image of God himself, with the potential and requirement to become like God. Before organized religion existed, there were religious rites and requirements of worship given to man to show his faithfulness to God.
Secondly, he had additional responsibilities added upon him to care for the earth and the animals, thus further separating mankind from the animal kingdom. Adam and Eve were NOT part of the animals, except that they also were commanded…to have sex.
When Eve was created, and before the Lord left them alone together (very important), they were also promptly married by the Lord.
“And the rib, which the Lord God had taken from man, made he a woman, and brought her unto the man. And Adam said, This is now bone of my bones, and flesh of my flesh…
Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh. And they were both naked, the man and his wife, and were not ashamed…” (Genesis 2:22-25; Moses 3:22-25; Abraham 5:16-19; italics added)
Man was instructed to have sex, but only after being married in the manner God required, further differentiating mankind from all other living things.
Then came the fall and mortality, and Adam and Eve completed their sexual cycle as commanded, and had children. They taught their children these same things. More commandments were added by the Lord in order to help them navigate the pitfalls of mortality.
The commandment to have married sex remains in force for us today. If we make the choice to follow it, practice it, and find ways to enjoy it, it can lead to great joy and bring us closer to our spouses and to God. If we choose to abdicate the responsibility the Lord has entrusted us with…there are many directions that choice can take us in:
We can worship sex for sex’s sake by choosing to engage in sexual behavior outside the boundaries of the Lord’s approval (marriage).
We can choose to interrupt the full natural cycle of sex by not having children.
We can even choose to avoid sex completely while being married.
But we cannot deny the commandment without receiving the consequences of that denial.
“To the first man and woman on earth, the Lord said, “Be fruitful, and multiply”. This commandment was first in sequence and first in importance…” (Oaks, Dallin H. “The Great Plan of Happiness”. Ensign, Nov 1993; emphasis added)