That's philosophy, not science. There is no evidence that circumcised men reproduce any worse, so needed it is not. On the other hand, that we don't need something is no indication removal is *necessary*.
Because variation in foreskin length exists enabling them to grow longer or shorter but no human had a spine suited to bepedalism so it had to adapt imperfectly.
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Have a look at the info I sent. We had foreskins way before we were human and they always served the same function. Changes in them to become longer & more complex are small but driven by something. Our spines did not serve the function they do now. We move completely differently
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I read it. The spine should then have a much greater impetus in changing than a foreskin that was functional as-is, right?
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Impetus? Evolution doesn't work by what it is most needed to do apropos of nothing. Variation needs to exist and certain traits be beneficial before it can make changes within a population.
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I have a duplex renal system and so does my mother. It caused both of us problems in pregnancy so we could only have one child. My daughter did not inherit it and so it has been naturally selected out. If it had been beneficial, we'd have had more children & passed it on.
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That isn't natural selection. That's just being lucky in not passing it on. If you hadn't been able to reproduce, it would have been NS'ed out.
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That is natural selection. It made us only able to have one child who had a 50% chance of inheriting it. If we'd been able to have more children, there would be more copies of it now. Instead, it came to an end with the first child who didn't inherit it.
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Natural selection works by the number of offspring a trait enables you to have and to survive. Someone who can have 10 healthy kids has ten times the biological fitness of someone who can have one & passes on 10X as many copies of their fitter genes.
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I agree.
End of conversation
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Spines come in greater or lesser curvature, they vary just like foreskins do. No difference there. But curvy spines are associated with disadvantages, so why hasn't that fixed itself if it happened with foreskins?
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Scoliosis is not directly heritable. If it were, it would have been naturally selected out because many people (my cousin) would have died before adulthood without the surgery that's available now. Its a deformity, not a naturally selected trait.
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If it kills people before reproducing, it will be selected for. Even if it isn't deadly scoliosis, lower back pain is endemic and makes people a lot less efficient in everyday life.
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Selected out, you mean? Yes, but it's not hereditary. If it were and it killed people before reproducing or made them unable to have sex or raise children, it would have been naturally selected out. The genes would not have been able to pass on.
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Then we agree: without a natural-selection level difference the gene expression makes, not much happens! That means that the foreskin isn't exactly a great contender for NS-mediated evolution, right?
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I don't know what you mean? Obviously the foreskin evolved by natural selection. How else would it have come to be?
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The foreskin came to be because it did. To claim every part of us is specifically optimized by evolution isn't correct. Some things just are good-enough and are there because they didn't get overly in the way.
End of conversation
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