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Mr.Samsa wrote:What difference between male and female sexuality?

Where to start

Do you think there are differences between male and female sexuality in other species or not?
As you probably think that irrelevant, do you think that human sexuality is competely learned? That we are born blank slates re. our sexuality?

It is actually difficult to tackle this with someone who only considers the here and now relevant, but I'll give it a go.

I want to go right back to anisogamy. I don't know how much you know about this but basically once upon a time ( )sex cells were of one size. Selection led to sex cells of two distinct types (I can discuss this in much more detail if you wish). At about the same time multi-celled animals evolved. These first animals were hermaphrodites (I can go in to the reasons this is most likely so if you wish) so bodies of one type produced the two types of sex cell ie not yet male and female bodies.

Selection led to two sexes which now experienced different selection pressures depending on whether they produced eggs or sperm.
While sharing more or less the same genome mechanisms evolved to alter development depending on whether the body was producing one sex cell or the other.
So we get sexual dimorphism.

If sexuality is the same for both sexes then how could sexual dimorphism evolve?

You could argue that it is just about primary sex differences that are necessary for egg and sperm to meet. But we also have secondary sexual traits, usually in males, which are about competition between them for sexual access to the other sex.
Standard sexual selection.
What we now realise is that there is no real division between primary and secondary sexual traits.
Male genitalia, for example, evolves from competition between males. Female genitalia evolves to discriminate between sperm.

Sexual dimorphism is the result of the different selection pressures on bodies that are producing sperm compared to bodies that are producing eggs.

We can get the extreme forms where males are minute and even live inside the female.
And we can get the ones we are more used to seeing in the animals around us.

Leap forward to apes as examples.
In which of the apes is male and female sexuality the same?

Gibbons form small pair-bonded family groups. Male and female are pretty much the same in bodies and behaviours. Ummm...interesting. While either sex may mate outside the pair-bond opportunistically, on the scale of monogamy/promiscuity they are at the monogamous end. Male and female reproductive interests are pretty much tied together in the very same offspring. Selection is pretty much the same on both sexes.

Orangs have the massive males and the much smaller females. No pair-bonding. Some males stay small though sexually mature and are able to harass and rape the females but females mostly mate with the big male in whose territory they live. Selection has acted differently to produce differences in bodies and behaviours.

Gorillas have the one-male family group again with the massive male and relatively small females. Males are very aggressive towards each other and infanticide by males is quite common as a means for males to acquire females. Selection has again acted differently to produce differences in bodies and behaviours.

(Of course the selection is very much in relation to the environment as well as phylogeny)

And again with chimpanzees and bonobos the sexual differences are quite clear. (I can go into details if you wish)

So your question 'What difference between male and female sexuality?' if you just mean humans implies that you think that humans are either monogamous and so have little difference like gibbons, which evidence very much goes against, or you think that humans have evolved something unique which means they can have different selection pressures on males and females but these do not affect their bodies and behaviours - any difference is about something else.

So you are suggesting that while in other species differential reproductive success within each sex is different and results from differences in bodies and behaviours and leads to the spreading of certain different traits in each of the sexes, in humans differential reproductive success has done nothing.

Or do you think differential reproductive success in other species also does nothing which is inherited?

Mr.Samsa wrote:And it's also necessary to understand how our evolved biology is massively shaped by learning and culture. Hence why indisputably biological things like hunger and thirst are often a function of learning and the environment.

From things you have said elsewhere I'm presuming that this is basically about pleasure/pain doing the teaching?

So if we see a difference in pleasure and pain between the sexes what would that tell us?

Two quite different examples.
Firstly back to hermaphrodites. In most, though not all, simultaneous hermaphrodites each one tries to avoid being inseminated while trying to inseminate the other. Is there some pleasure connected to insemination and pain connected to being inseminated? Why would that be? In some cases there is in fact genuine pain - being stabbed and the seminal fluid burning through the skin, for example. But even in the case of fish where the gametes are simply being released there is still this difference. It would appear to be painful to release eggs but not sperm? So we get 'sperm' trading where the most keen to mate releases eggs first - does the more painful thing? - and then the exchange commences.
Why have they evolved to experience different pleasure or pain in relation to eggs and sperm do you think?

In the few hermaphrodites where it seems to be preferable to receive the sperm it appears to be because the sperm is digested ie used as food rather than to fertilize eggs. Far less painful when sperm is a useful food source. (Then we get males evolving chemicals in the ejaculate or the 'love darts' of snails which stop their sperm being digested by the mate).

Secondly a quite different example, chimpanzee (and bonobo) female dispersal.
Males always stay in their birth group, females mostly disperse.

There was a fascinating tv documentary recently about a community of chimpanzees that has become isolated in a steep narrow valley. The land around them was bare and dangerous to venture in to. One female had reached puberty and kept going to the edge and looking across the bare land. She actually did set off to find a new community but returned a few days later having obviously failed to cross the bare land even though it was only a few miles to forest and other chimpanzees.

So the males, presumably, feel pleasure in remaining in their birth group but the females when they reach puberty feel pain and seek pleasure elsewhere? The sexes experience differences in pleasure and pain? Why? Does this not mean that they have some innate difference which means they experience these pleasure/pain differences?

Mr.Samsa wrote:I don't deny that, generally, people would prefer to decide the specifics of their reproductive cycle, but this hasn't been demonstrated to be evolutionary.

It is the very root of evolution.
It is sexual selection.

It is not about conscious decision making necessarily but as you might argue it is perhaps about pleasure and pain. Hence the extreme pain women feel regarding true rape.
Or that girls feel in societies where they are married off to men twice their age or older though no doubt a pleasure for the men.

It would be a very unfortunate state if we had a situation where men and women were assumed to have the same pleasure/pain experience rather than different ones. I'm sure this is part of the problem regarding sexual rejection for men. Even some have asked this question on these forums, and a gay friend once asked me the same ie why not just enjoy the sex? So we get all kinds of theories from men about how women are teasing them, leading them on, manipulating them, being vengeful etc etc. If men think women really feel the same as they do about sex ie any sex is better than none, then we have a serious problem.

This is not like hunger or thirst which is the survival part of natural selection, it is about sex/reproduction which is about two different sexes where selection acts differently (except in true genetic monogamy).

If you then argue that the differences men and women feel about pleasure in connection to sex is learned then if women say that 'actually that experience was painful' the response from him is that it is only because she has learned incorrectly? Could she not argue that, no, his pleasure in that experience is because he has learned incorrectly? Who decides?

Sex is not about sharing fluids but about a one way journey of sex cells from him to her. Not a minor difference.