We only have genitals because we have two sexes: male and female. Sexual reproduction evolved eons ago and far back in our evolutionary history.
Many plants and animals reproduce sexually. The male genetic material is mobile and plentiful. The female genetic material is stationary. After fertilisation, the embryonic cells (a combination of egg and sperm cells) divide and grow within the female reproductive anatomy or part (of a plant). This standard definition of male and female is used throughout nature. Female mammals are easily dominated by their male counterparts. We can see males servicing females in other species of animals. Even insects, such as ants and bees, have workers (males) who service a static female queen.
The male spermatozoa (genetic material) are tiny (relative to the size of the egg) and mobile. There are millions of them (compared with one egg) so they are more dispensable. Sperm typically cover some distance to reach the egg (or ovum). A man’s sperm are produced regularly from his testes throughout his life (until old age). The tiny spermatozoa, together with other glandular secretions, are ejaculated from the penis and referred to as semen.
The female genetic material (called ova or megaspores) contains the necessary nutrients for the developing young and so is relatively large. A girl is born with her genetic material: immature eggs. These are released (one at a time) from the ovaries into the uterus on a monthly schedule from puberty until a little after her last period (menopause) in late middle age.
Every foetus starts out with the building blocks for both male and female reproductive organs. All embryos (regardless of sex) have Wolffian ducts and Müllerian ducts. These two sets of embryonic ducts determine our ultimate internal reproductive anatomy and consequently our sex. Development of our internal reproductive anatomy depends on hormones produced by the testes (a lack of hormones for a female). In most foetuses only one set of reproductive ducts (male or female) develops. A process called atrophy inhibits the development of the superfluous anatomy.
In a boy the Wolffian ducts develop into the male reproductive organs. The male ducts form the vas deferens (that connects the testes to the penis) as well as other tubes required for ejaculation of semen. In a female these ducts waste away. A man can ejaculate semen, including sperm (male genetic material) because of these glands and tubes that women don’t have. This is clear anatomical evidence that women are incapable of ejaculation.
In a girl the Müllerian ducts form the female reproductive organs. The female ducts form the vagina, which leads into the womb (uterus) where the foetus develops before birth. In a male embryo these Müllerian ducts disappear. This is clear anatomical evidence that the vagina (anatomy that is not present in the male) is not involved in orgasm, which is a basic human response common to both sexes. Male ejaculation is the only justification for orgasm. Female orgasm is a hangover from how the sexes have evolved.
Men can’t have babies because they don’t have women’s reproductive biology. Everyone accepts this logic because men don’t want babies. But men do want women to have orgasms as and when they do. So the logic that women don’t have men’s reproductive biology is not accepted. Sexual politics motivates adults of both sexes to promote the idea that women should orgasm from stimulation of their reproductive anatomy (the vagina).
Men are lucky. The penis is both a reproductive organ and a sex organ. Unfortunately, the same is not true for the vagina. The vagina complements the penis but only for reproductive purposes. Nevertheless, men’s sex drive means that they would ideally like a partner to be equally enthusiastic about engaging in intercourse. Men ignore the anatomical precedents, which indicate very clearly that orgasm is achieved through anatomy that parallels the male (the clitoris) rather than anatomy that complements it (the vagina).
Some women assert that they have a right to have orgasms but we cannot decide to have an orgasm whenever or however we want. Orgasm occurs naturally when a person is responsive. Responsiveness is a physiological response that arises subconsciously as a result of how our brain responds to eroticism. But responsiveness is a male characteristic. Men routinely experience orgasm whereas female responsiveness is rare. This explains why there is so much mystery and ignorance surrounding female orgasm.
There is a great deal of anatomic and clinical evidence that most of the interior of the vagina is without nerves. A considerable amount of surgery may be performed inside the vagina without need for anesthetics. (Alfred Kinsey 1948)