What Sperm Reveal About Sexual Morality

Sexual morality and marriage

A version of this article on sperm and sexual morality originally appeared on Catholic Stand.

When observing an object, we naturally want to know the purpose(s) for which it is made. For example, if I want to know the purpose of a car engine, I might ask the manufacturer or a mechanic. Knowing my desire to understand this particular thing about car engines, the manufacturer or mechanic will tell me that car engines are made for the purpose of turning fuel into active energy for cars.

Likewise, when I observe parts of the human body, I naturally want to know the purpose(s) for each part. A cursory study of the human heart tells me it is designed for pumping blood throughout the body. A study of the human brain tells me it is designed for processing sensory knowledge and integrating the human body’s varying parts into an organized whole.

The human reproductive system also has its own purpose. A study of human sperm cells tells me that they have the single purpose of fertilizing the human egg (ovum), and the sperm’s tail has the single purpose of propelling the sperm to the ovum.  Accordingly, the male’s half and the female’s half of the reproductive system are designed to assist the sperm in reaching the egg (regardless of any defects in the system). Clearly, the female’s half of the reproductive system is designed to receive the male and his sperm.

This should tell us something about sexual morality. Today, we might say that we are “just following the science.”

Marriage, Procreation, and sexual morality

Given the above, we can see that the sexual act is ordered toward procreation (even if procreation cannot or does not occur) because the sperm’s single purpose is to seek its counterpart, the ovum. Also, the sexual act is ordered toward union between one male and one female for obvious reasons.

This ordering implies that the sexual act’s purpose is to create children, which is accomplished through the organic (meaning “of the organs”) union of one man and one woman in the sexual embrace. These newly created children have one mother and one father.

Due to the sexual act’s design to bring about the existence of other human beings and organically unite a man and a woman, marriage is the divine construct under which this act should occur. In marriage, properly speaking, one man and one woman promise themselves to each other for their reciprocal care, for the care of their potential children, and for the care of society (familial, secular, and ecclesial). After all, human beings are not just detached individuals. They are born into families and societies and are designed to participate in the common good.

Also, because the mother and father have created a human being, they must provide their child with a lifelong example of female and male complementarity. They have a duty to show their child how a good man and woman should live and how they should love one another through the good times and the tumultuous ones.

Dr. J. Budziszewski, a Catholic philosopher, writes, “A parent of each sex is necessary to teach the child, because the child needs a model of his own sex, a model of the other sex, and a model of the relationship between them. Mom and dad are jointly irreplaceable” (The Meaning of Sexual Powers).

Additionally, Scripture tells us that marriage is designed to reflect the sacrificial marriage between Christ and His Bride, the Church. Christ loves His wife so much that He sacrificed Himself to save His bride as an example of supreme love.

Divorce, Remarriage, and sexual morality

Because marriage is designed to be a lifelong commitment, human beings have no authority to terminate a valid marriage. Jesus said, “What God has joined together, let no man put asunder” (Mark 10:9). Therefore, a civil divorce has no effect on the marital bond. It may somehow serve the spouses in dividing property and rendering custodial decisions, but it cannot dissolve a sacramental marriage. It is merely a piece of paper issued by the state for legal purposes. Accordingly, any “remarriage” is an adulterous relationship.

Contracepting and sexual morality

Because sex is designed to be the total giving of a man and woman to one another, contracepting is opposed to sexual union and is, therefore, an offense against marriage. Contracepting is the deliberate interference with sexual intercourse to prevent conception. Because the sexual act is ordered toward conception, contracepting is an inherently contradictory action.

Contracepting is not only designed to prevent conception, it also prevents organic union. Contracepting intentionally frustrates the mutual sharing that should be present in the sexual embrace. The result is mutual objectification (i.e. lust, using each other purely for sexual pleasure rather than lovingly embracing each other for union and procreation; cf. CCC 2370).

Artificial Insemination, In-Vitro Fertilization, and sexual morality

Because marriage and the sexual embrace are designed to be between one man and one woman, a third party must not directly intervene in the sexual act. In other words, a medical professional must not artificially fertilize an ovum inside or outside the uterus.

The Catechism states, “Techniques that entail the dissociation of husband and wife, by the intrusion of a person other than the couple (donation of sperm or ovum, surrogate uterus), are gravely immoral. These techniques (heterologous artificial insemination and fertilization) infringe the child’s right to be born of a father and mother known to him and bound to each other by marriage. They betray the spouses’ ‘right to become a father and a mother only through each other'” (2376).

It further states, “Techniques involving only the married couple (homologous artificial insemination and fertilization) are perhaps less reprehensible, yet remain morally unacceptable. They dissociate the sexual act from the procreative act. The act which brings the child into existence is no longer an act by which two persons give themselves to one another, but one that ‘entrusts the life and identity of the embryo into the power of doctors and biologists and establishes the domination of technology over the origin and destiny of the human person'” (2377).

Fornication, Pornography, and sexual morality

Fornication is sex between two unmarried people. Because the man and women do not make a sacred promise to join together for the sake of each other, their potential children, and society, they seek to objectify one another through sex in this type of relationship. In other words, the man and woman have sex just for the fun of it. Although sex is designed to be pleasurable, pleasure is not the end for which sex was created. Rather, pleasure is part of the motivation for sex (CCC 2353).

Likewise, pornography takes what should be a sacred union between a man and woman and puts it on display to be objectified (CCC 2354). Masturbation turns the sexual act inward, seeking self-gratification rather than a loving embrace between a married person and his/her spouse (CCC 2352).

Adulteryand sexual morality

Adultery is sex between a married person and another who is not the married person’s spouse. In adultery, like fornication, the two participants seek to objectify one another. This sexual embrace not only violates the marital promise, it seeks to disrupt and even destroy the family unit (CCC 2380-2381).

Homosexual Behavior and sexual morality

Regarding homosexual attraction and behavior, one, and only one, conclusion can be drawn the above. If a human being desires to have sexual intercourse, he/she must do this with someone of the opposite sex. If the sperm is designed for the ovum, then the sexual act must be with someone in whom the ovum is designed to exist.

Our entire reproductive system screams this message so loudly that one must purposely deafen oneself, figuratively speaking, not to hear it. Thus, the sperm is clearly not designed for other areas of the body, male or female. As such, the Church teaches that sexual attraction to someone of the same sex is a psychological disorder (the Church’s term to describe the homosexual orientation is “intrinsically disordered”) and should be treated as such. Homosexual behavior, like the other sins mentioned, is a grave sin.

Because marriage is intended to be a committed relationship between people who are ordered toward organic union and procreation, homosexual “marriage” is nothing more than a charade. It exists on government issued documents only and not in reality.  This is because homosexual couples are not ordered toward organic union and procreation.  Thus, anyone who advocates for homosexual “marriage” advocates for pure fantasy and denies reality.

Additionally, our actions have an end to which they ought to be directed and an end to which they are actually directed. Human sexuality ought to be directed toward union and procreation. Thus, sexual activity that intentionally frustrates this end is evil. It would be like purposely filling one’s lungs with water. The lungs are not created for that end, and intentionally filling them with water would frustrate the lungs’ proper purpose and end.


You are the gender with which you were born regardless of any emotional or psychological issues you may have. If you are someone ordered toward producing sperm, you are clearly designed to be a male. The same goes for females (those ordered toward producing ova). So, those who suffer from some transgender disorder should seek psychological help because this is not a natural orientation or behavior, and it is not a physical problem.

Those who support transgender behavior and related medical practices are in a particularly grave spiritual position. They choose to encourage these people’s actions despite knowing that they need psychological help. Hell awaits them if they do not turn away from this horrific ideology and stop supporting physical mutilation for these mentally ill people.


Because we are created with intellectual powers, including the power to choose, we are accountable for the decisions we make. God orders every human being toward understanding and choosing. Therefore, when we abuse these God-given powers, we work against our own nature and the Nature-Giver, and we fall into a state of sin. Being that God is Justice, He will ensure perfect justice is meted out to each and every person.

All of this from understanding the microscopic sperm cell’s single purpose.