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> Something has deeply deeply changed in society for a fertility rate to go from 6 to 0.8 in 60 years Does the change necessarily have to be societal? > In 19

by ctoth 4y ago

> Something has deeply deeply changed in society for a fertility rate to go from 6 to 0.8 in 60 years Does the change necessarily have to be societal? > In 1992, a study found a global 50% decline in sperm counts in men over the previous 60 years. Multiple studies over subsequent years confirmed that initial finding, including a 2017 paper showing a 50% to 60% decline in sperm concentration between 1973 and 2011 in men from around the world. These studies, though important, focused on sperm concentration or total sperm count. So in 2019, a team of researchers decided to focus on the more powerful total motile sperm count. They found that the proportion of men with a normal total motile sperm count had declined by approximately 10% over the previous 16 years. The science is consistent: Men today produce fewer sperm than in the past, and the sperm are less healthy. The question, then, is what could be causing this decline in fertility[0]. [0]: https://theconversation.com/male-fertility-is-declining-studies-show-that-environmental-toxins-could-be-a-reason-163795 https://theconversation.com/male-fertility-is-declining-stud...

shadowofneptune 4y ago
Infertility is not the leading issue when people are asked, 'why are you not having children?'. Until it is, I don't see how it can be more important than societal barriers.
- adrianN 4y ago
  Lower sperm count and lower desire to have children might have a common cause.
  - akvadrako 4y ago
    Lower desire might even be causing lower sperm counts. Anyway, sperm counts are not outside the normal range. It was just that certain groups had higher than needed levels.
Aeolun 4y ago
The same things that cause a higher average life expectation? Maybe the microplastics floating through the atmosphere everywhere? The constant stress about what is happening with the whole world instead of just your neighbor?
Dalewyn 4y ago
>Men today produce fewer sperm than in the past, and the sperm are less healthy. The question, then, is what could be causing this decline in fertility[0]. This has everything to do with monogamous relationships and marriages in most of the developed human world. In the natural world, there are many factors at play that help ensure only the "healthiest" males conceive with females. Most factors are indirect, such as males physically fighting each other for a mate wherein the "fittest" male would more likely come out superior and successfully mate. One direct factor that has been practically eradicated from humanity, however, is direct competition between sperm. Some animals and many plants are polygamous, wherein a female receives sperm (or other forms of genetic material as applicable) from multiple males. The sperm have to compete with each other to reach the egg first and conceive, this encourages males with the "healthiest" sperm to pass their genetic material onto the next generation. Monogamous relationships and marriages as seen in humans remove this factor completely, the "fitness" of a given male human's sperm is irrelevant to conception because competition between sperm has ceased to exist. Both unfit and fit sperm alike can conceive, assuming other indirect factors at play allow for it. Indirect factors that care not for the "fitness" of sperm.
- jhanschoo 4y ago
  That's an elaborate portrait and narrative you've painted there. Do you have sources for that?
  - Dalewyn 4y ago
    It was something I saw many years ago on NHK as one theory of why human sperm quality keeps deteriorating. As far as I'm concerned, it makes sense to me. Remove more and more factors that would encourage healthier sperm and it's only natural that our sperm will deteriorate.
    - amag 4y ago
      As others have said, the decline is much too rapid in the last couple of decades for it to be explained by evolution. It sounds more like a theory spouted by chemical-/food-/etc companies who worry about getting the blame.
phatfish 4y ago
When you can't afford to have children due to low pay, sperm count is out of the equation. What doesn't make sense to me is the people that are concerned about society "changing", the native population not having enough kids, we are being "overrun" with immigrants etc. Are the same people that refuse to vote for politicians advocating higher minimum wages, more benefits and fairer taxes. It can't work both ways, either you want to crush the average person with low wages and taxes, or you want the native population to thrive. No one is going to subject themselves to poverty to help balance the demographics for the privileged.

by ctoth 4y ago

shadowofneptune 4y ago

Infertility is not the leading issue when people are asked, 'why are you not having children?'. Until it is, I don't see how it can be more important than societal barriers.

adrianN 4y ago
Lower sperm count and lower desire to have children might have a common cause.
- akvadrako 4y ago
  Lower desire might even be causing lower sperm counts. Anyway, sperm counts are not outside the normal range. It was just that certain groups had higher than needed levels.

Aeolun 4y ago

The same things that cause a higher average life expectation? Maybe the microplastics floating through the atmosphere everywhere? The constant stress about what is happening with the whole world instead of just your neighbor?

Dalewyn 4y ago

>Men today produce fewer sperm than in the past, and the sperm are less healthy. The question, then, is what could be causing this decline in fertility[0]. This has everything to do with monogamous relationships and marriages in most of the developed human world. In the natural world, there are many factors at play that help ensure only the "healthiest" males conceive with females. Most factors are indirect, such as males physically fighting each other for a mate wherein the "fittest" male would more likely come out superior and successfully mate. One direct factor that has been practically eradicated from humanity, however, is direct competition between sperm. Some animals and many plants are polygamous, wherein a female receives sperm (or other forms of genetic material as applicable) from multiple males. The sperm have to compete with each other to reach the egg first and conceive, this encourages males with the "healthiest" sperm to pass their genetic material onto the next generation. Monogamous relationships and marriages as seen in humans remove this factor completely, the "fitness" of a given male human's sperm is irrelevant to conception because competition between sperm has ceased to exist. Both unfit and fit sperm alike can conceive, assuming other indirect factors at play allow for it. Indirect factors that care not for the "fitness" of sperm.

jhanschoo 4y ago
That's an elaborate portrait and narrative you've painted there. Do you have sources for that?
- Dalewyn 4y ago
  It was something I saw many years ago on NHK as one theory of why human sperm quality keeps deteriorating. As far as I'm concerned, it makes sense to me. Remove more and more factors that would encourage healthier sperm and it's only natural that our sperm will deteriorate.
  - amag 4y ago
    As others have said, the decline is much too rapid in the last couple of decades for it to be explained by evolution. It sounds more like a theory spouted by chemical-/food-/etc companies who worry about getting the blame.

phatfish 4y ago

When you can't afford to have children due to low pay, sperm count is out of the equation. What doesn't make sense to me is the people that are concerned about society "changing", the native population not having enough kids, we are being "overrun" with immigrants etc. Are the same people that refuse to vote for politicians advocating higher minimum wages, more benefits and fairer taxes. It can't work both ways, either you want to crush the average person with low wages and taxes, or you want the native population to thrive. No one is going to subject themselves to poverty to help balance the demographics for the privileged.