Here I summarise this essay by Andrew T. Walker, entitled, ‘Gender and Sexuality’.

Gender refers to the biological differences between males and females and to the different cultural ways in which creational distinctions are expressed.  Sexuality refers to God’s design for the procreative relationship between men and women and to the experience of erotic desire within that relationship.

Sexuality and gender in God’s design

Several axiomatic truths related to gender and sexuality are found in the Genesis 1–2 narrative.

1. ‘God created. Reality and human experience are not self-creating or self-constituting. Christians confess that the God who creates the cosmos is the holy, sovereign, and just God who orders all aspects of reality—including sexuality and gender.’
2. ‘God created humanity. God is the creator of humanity, and as such, has the right to speak authoritatively over our lives. We are his subjects, and sexuality and gender are constitutive aspects of God’s rule over humanity…Sexuality and gender, then, are not plastic and endlessly malleable to fit human preference…Christians believe that gender and sexuality are purposefully ordered to fit God’s will for humanity (1 Cor. 6:13). This means obedience and a commitment to living in line with God’s creative will is where holiness and human flourishing form an intersection.’
3. ‘God created humanity in his image. Genesis speaks of God making man and woman in His image…We image God in our relational dimension, our structural design, and our functional capacity…Humanity existing in male and female iterations implies that our sexual design and gendered existence are participants in the fundamental nobility and dignity that human beings are said to possess because of being made in God’s image.’
4. ‘God created humanity male and female. ‘God created humanity…made humanity in male and female forms…Male and female, according to the biblical portrait, are fixed, bodily realities; meaning they are not interchangeable or eradicable. They are objectively known; such that the identity of who we are as sexed humans is not a mystery. Lastly, male and female imply substantive differentiation. This differentiation is observed down to the chromosomal, anatomical, reproductive, physiological, and emotive levels. This physical difference starkly manifests itself in the anatomical design of male and female, which makes procreation possible and the fulfillment of the cultural mandate actionable.’
5. ‘God created male and female for one another. God commands sexual activity to be experienced exclusively within the marital relationship of one man and one woman…In Scripture, sexual union ratifies the marriage covenant, signifying the existence of the marriage union intended to be permanent, monogamous, and exclusive (Gen. 2:24; 1 Cor. 6:16). Notice in Genesis 1:26–28 that the creation of man and woman in Genesis both is structural and dynamic. As male and female beings made in God’s image, their design is ordered toward a particular purpose—filling the earth, subduing it, exercising dominion. More specifically, that purpose is accomplished by male and female design—that the act of being fruitful and multiplying hinges on, and springs from, their respective sex distinction.’

These axioms do not pertain to Christian believers only.  They stem from God’s creational purposes for all humankind.

Sexuality and gender in revolt

Human sin leads us to seek to overturn each of these axioms.

1. ‘Concerning axiom one, a culture of unbelief either rejects God’s existence or God’s authority…Nowhere is this more apparent than in the never-ending redefinition of sexual morality and ensuing gender confusion.’
2. ‘In axiom two, humanity denies that it is a divine creation born of an intelligent and divine will, or inscribed with any inherent, fixed meaning. Any sexual arrangement is thus allowable insofar as consent is present; and any gender expression is permissible insofar as it comports with a person’s self-perception.’
3. ‘With axiom three, humanity divests itself of any particular calling in light of being made in God’s image. Since we are not special creations endowed with a mission to exercise dominion, we subsist by vain expressions of human autonomy and self-seeking justification.’
4. ‘In axiom four, humanity denies that male and female are objective and fixed realities. Instead, gender fluidity and suppression of sexed realities paint a portrait of gender and sexuality that is endlessly malleable and psychologically grounded.’
5. ‘In axiom five, the beauty of male-female complementarity is denied, meaning that the creational guardrails for sexuality are nullified.’

Sexuality and gender in redemption

1. ‘The New Testament reaffirms the vision for gender and sexuality taught in Genesis…In Matthew 19, Jesus affirms that the creational pattern for male and female set forth in Genesis 1–2 remains authoritative and binding for humanity. In Acts 15, the earliest church leaders confirmed that obedience to Old Testament law was not expected for Gentle Christians, but Christians were expected to uphold the same standard of Old Testament sexual morality inaugurated at creation….New Testament prohibitions on sexual practices (e.g., homosexuality, incest) are echoes of the Old Testament’s sexual ethic…The New Testament makes clear that sexual rebellion and rejection of appropriate gender boundaries renders culpable before God’s judgement (1 Cor. 6:9–11).
2. ‘The gospel brings fulfilling clarity to the vision for gender and sexuality taught in Genesis…In Ephesians 5:22–23, Paul explains that the union of husband and wife is meant to foreshadow the most visceral union in the cosmos—the Christ-Church union.’
3. ‘The gospel empowers Christians to live in accord with the biblical vision for gender and sexuality taught in Genesis. The gospel of the Lord Jesus Christ calls us to glorify God with our bodies because they were purchased by Him (1 Cor. 6:20). This purchase comprises the whole man (2 Cor. 5:17). We are called to honor the Lord Jesus and to submit to Him our sexual desires as well as our conduct (Matt. 5:28; Gal. 5:19–21; Eph. 4:22–24; Col. 3:5; 1 Thess. 4:1–8). We are to flee all forms of sexual morality (1 Cor. 6:18; Eph. 5:3–5; 1 Thess. 4:1–8). We embrace appropriate gender norms so as not to scandalize or give offense with impropriety of gender expression (Deut. 22:5; 1 Cor. 6:9; 11:3–16; 1 Tim. 2:9). Christians believe that we are not our own, and that we owe every facet of our existence—our gender expression and our sexuality—to Jesus Christ (Col. 1:15–20).’