For many of us, the attraction to mate is so powerful that we seek intercourse despite no looking to have children. This is unusual, in so much as most mammals and animals on our planet only have intercourse or mate in order to generate offspring. So why are humans different? Well, some would say that we are the dominate race on this planet because or desire for intercourse is different to all other species of animal and the fact that it is so strong makes our desire for intercourse immeasurable.
But if the female species, or female human beings to be more precise, do not need to arrive at orgasm, then why do they have them at all? Unlike a man, who must reach orgasm in order to ejaculate, a woman on the other hand, still produces eggs and, obviously, can create offspring without orgasm. Some medical experts state that the female orgasm is a byproduct of our similar make up at the embryo stage of life. For a male embryo, at around the sixth week, the SRY gene, on the Y chromosome promotes a protein called the H-Y antigen. The effect of this is to bind to the DNA molecule itself, in a number of specific places, causing it to bend, in turn affecting the action of a number of genes. About nineteen different genes are probably involved, on either the X chromosome. The actual sequence of events is still largely unknown, but the hormone producing cells of the indifferent gonad become the Leydig cells, the primitive testes, which have rudimentary sperm producing tubules, while the supporting cells become the sertoli cells which will, in time, produce the sperm. They also have the ability to produce testosterone and other androgens, along with a hormone called Mullerian Inhibiting Factor. The latter, as its name implies inhibits the further development of the female sexual features, which degenerate.
In a female embryo, from about the sixth week, the Wolffian ducts degenerate, and the Mullerian ducts develop towards the Fallopian tubes, uterus and vagina. Meanwhile, by the twelfth week, the indifferent gonad begins to develop into an ovary.
The supporting cells form the cells which will surround the ova, the granulosa cells, and the hormone producing cells form the thecal cells which remain relatively quiescent. The chromosomes in the gamete cells begin to separate, but then cease their activity until puberty.
As early as 1983, the idea of femaleness being merely the absence of maleness was out of date. As Rose, Lewontin and Kamin point out, there is a specific 'feminisation' process. Clearly there must be two X chromosomes, otherwise the gamete cells die, as in X0 (Turner's Syndrome), and the ovary atrophies. Moreover there is a rise in estrogens in the female embryo at six weeks, paralleling the rise in androgens in the male.
Therefore, until the eighth week, the external genitalia grow identically for either sex, but by twelve weeks, for a female, the genital tubule develops into a clitoris, while the urogenital membrane develops towards the labia. Which could be the reason why women orgasm at all. That the female body, being so similar to the male until the eight week, could simply be “left” with the ability to orgasm and therefore this remains as a trait within the female gender.
The offshoot is that a man will seek intercourse even though there is no intention of seeking children and the woman’s rewards mechanism for intercourse remains intact and, as such, may lead to promiscuity as a “general design” of the human species as a method to coax multiplication and growth of the species through child birth.