How can the mechanism of pleasure experience (orgasm) during copulation be explained from the theory of evolution?

Answer

As for the male orgasm, it is obvious that it is a positive adaptation that increases reproductive success. A male animal that experiences a feeling of happiness when copulated with a female will be more motivated to repeat this behavior than competitors who do not know this motivation. And the more often the male animal copulates, the greater the chance of continuing its genes (including those that enable the feeling of happiness).

The man needs the orgasm to ejaculate. But the woman does not need an orgasm to conceive. In the woman, in contrast to the man, there is no reproductive function for the orgasm. There is no indication that women with more orgasms are more fertile.

Scientists have long puzzled over whether the female orgasm has an evolutionary function, with no generally accepted conclusion.

There are three main hypotheses about the female orgasm:

1) The man needs the orgasm for ejaculation. Did the woman retain the ability to orgasm because her reproductive system has the same origin as the man’s? One can make the comparison with the nipples, which also exist in the man but have no function. They are there simply because the same trait confers a reproductive advantage in the opposite sex (feeding the children). Indeed, the woman’s clitoris is made of the same fetal tissue from which the man’s penis develops.

2) Is orgasm an evolutionary novelty (in primates) whose function is to form a faithful couple? The woman also wants sex when she is pregnant or is already raising several children. This would then serve for partner bonding: the man does not have to look for another partner to get his money’s worth and thus contributes to child care. This increases the chance that the offspring will mature and in turn pass the genes on to the next generation (reproductive advantage). Or else the female orgasm may also serve to increase the frequency of sex (keep trying until it works). This increases the chance of fertilization.

3) New hypothesis: the female orgasm has no evolutionary function but is derived from ancestral animals in which copulation stimulated ovulation. In rabbits, for example, copulation, or even the presence of a male animal, leads to ovulation in the female. This is accompanied by an increase in the hormones oxytocin and prolactin that are triggered by copulation. In primates (and humans), ovulation occurs spontaneously, without external influences (but through an internal hormonal cycle). But women still undergo the same hormonal changes that the researchers have observed in eg rabbits, especially an increase in oxytocin and prolactin during orgasm, according to these researchers.

The induced ovulation of our ancestral mammals would thus be the evolutionary predecessor of the human, female, orgasm. But it has lost its original evolutionary function (ovulation regulation).

Which hypothesis is correct? I don’t know. An important problem that complicates this research is that the existence of orgasm in other animal species is difficult to determine unambiguously. From when in evolution does the orgasm exist? Does a fish experience a sense of delight when it releases its sperm or eggs into the water? This is subjective and difficult to figure out.