Are we in a fertility crisis?

Are we in a fertility crisis?

Last month the global population hit 8 Billion people Now like me that is the number I can say That cannot really comprehend it's big Basically And the number of people on the planet Are projected to keep growing to 9.7 Billion by 2050 and 10.4 billion by the End of the century But the rate of population growth is Declining According to the un's latest reports in 2021 the average fertility of the World's population stood at 2.3 baths Per women over a lifetime having fallen From about five births per woman in 1950. Global fertility is projected to decline Further to 2.1 baths per Woman by 2050. Put that into some perspective a birth Rate of 2.1 bars per woman sustains the Current population size and you can see Here nicely how the fertility rates Impacts population sizes over just three Generations But that's on the population scale and Two-thirds of the global population live In a country or area where fertility is Below 2.1 bars per woman now there are Obviously many potential explanations For these changes but the one I will Further discuss today is about fertility And whether we really are in a fertility Crisis and what we can do about it

So firstly what do I mean by fertility Here Well we're navigating the literature you May come across two definitions the case I have used so far is the more Demographic sense or statistical way of Describing the number of children born The fertility rates or there is the Biological definition which I'll Probably refer more to throughout the Rest of this video that is of fecundity By the one can actually reproduce So is there evidence for a decline in Fertility Well a landspot paper came out in 2017 Where their key finding was a Significant decline in sperm counts Measured by spam concentration and total Spam count between 1973 and 2011 driven By a 50 to 60 decline among men Unselected by fertility from North America Europe Australia and New Zealand This paper was co-authored by Dr Sharna Swan whose book countdown I read a year Ago and one I would highly recommend Though I did also slightly terrify me And now we have the latest updates for The studies published between 2014 to The end of 2019. to see whether the Trends continued post-2011 and the Authors were also interested to see if The trend spread to South America Africa And Asia So again in this matter analysis study

They looked at spem concentration and Total spam count from published studies That fitted their criteria they then Combine the data with their previous Paper Not only did they see the trends Continue but they also found by looking At time intervals that there was a Marked increase in the percent Decline And spam concentration And they found strong evidence for the First time of a decline in sperm counts Among men from South Central America Asia and Africa there are of course some Caveats to be aware of in studies like This one that it is just a meta-analysis And that they focused on spam count not Sperm motility or morphology which have Also been associated with fertility but That said sperm count does have Implications as it has been closely Linked with male fecundity and reduced Sperm count has been associated with Testicular cancer And increased all-cause mentality and Morbidity but the spam is just one half Of the equation but unfortunately while There are multiple reports now when Trends are male reproductive Health There are not any for female Reproduction It's not that I'm just trying to avoid It but either way it raises the question Of why why is there this decline

Our human populations living in Industrialized regions at risk of a Catastrophic decline Well that is the opening of a recent Review article environmental factors in Declining human fertility an interesting Read that seeks to investigate the Reasons that may be behind this decline In sperm count is this decline driven by Genetics or environmental factors Well according to this review no single Genetic Factor has been shown to affect Fertility on a population scale And two immediate explanations Hawaii Are one the global rate of the client Seems to be fast to be driven largely by Genetics and two if there was a genetic Variant that made someone less fatal Then that person would be less likely to Pass on that trait to the Next Generation the theory of natural Selection Although that said one could argue that With multiple assisted reproductive Technologies now available You could bypass this natural negative Selection pressure enabling the Accumulation of genetic variants that do Affect fertility moreover with cheaper And more in-depth DNA sequencing tools More studies are now being conducted Into reproductive aging to find genetic Variants that are linked with the basic Biology of gametogenesis and

Reproductive longevity Interestingly many of these genome-wide Association Studies have identified DNA Damage repair to be involved So the genetics is still unclear but What about epigenetics how the genetic Information is read well epigenetic Marks are Dynamic and can be affected by Lifestyle and environmental exposures And evidence is accumulating in animal Models that epigenetic patterns can also Be inherited across Generations this Could be through DNA methylation marks Or the presence of small rnas that are In the sperm or egg It is a much harder to test this in Humans though Although one human study found the micro RNA an RNA that influences gene Expression as an auspicious Omen of In-future fertilization Effectively here they showed that higher Expression of the micro RNA HSA microrna 191 was associated with higher Fertilization rates in IVF Though while this is interesting Research it still doesn't actually Address the question of the current Cause of Decline and spam counts Esters Microenabing depleted over time what Would be the cause of it or what are the Other courses is it Environmental Now doctors want to expose this Extensively in her book she discusses

Weights being substantially over Underway it's linked with negative Effects on sperm quality and increased Risk of miscarriage for females smoking Amount of exercise and stress and you Have a topic that both took this one and The truth you mention are modern Chemicals and industrialization So things like phthalates BPA and Pesticides which are found in everyday Items but there are no causal studies Only correlations And I did some research into finding Some evidence for this and one small Study I came across found no link Between BPA levels and body fluids and Couples undergoing IVF but other Studies Have so I'll put some links to the Papers in the description And going back to what we were saying About epigenetics it could be that these Environmental exposures or lifestyle Choices of parents and grandparents Could influence the fertility of those Of reproductive age today the fact is It's hard to prove any of this But what can we do about it Well there are obviously options Available today such as IVF and other Assisted reproductive Technologies as Well as egg and tissue freezing but These things aren't necessarily cheap And they can be invasive and have Associated risks moreover they treat the

Problem they don't actually fix the Cause of the issue Unfortunately but evidently there is Just a massive Gap in our understanding Of what happens during the early stages Of pregnancy for developing fetuses and How this all impacts reproductive Potential and health And why does decline is occurring and What can be done to rejuvenate it And I think the best phrase to summarize All this comes from this review article The difficulty in distinguishing between Biological or behavioral factors Including educational attainments that Affects human fertility has had Researchers to conclude that the Question on the causality underline the Decline in human fertility cannot be Answered but I do like to Amber some Good news and while there is some good News that is research is being conducted As we become aware of this problem But it's not just a scientist problem it Also involves governments and health Authorities But some of the basically biological Research being conducted I spoke about Earlier this year called in featuring Gametogenesis that is the generation of Spam and egg in a dish instead of Deriving them directly from the body so You can take an induced periprotein stem Cell and convert it into a precursory

Form of an egg and sperm and then use Different culture methods to mature them This has been done to create fertile or Springer mice although at the moment With extremely low efficiency if you'd Like to learn more about this technique Then you should watch this video here But with that I hope you've learned Something in this video thank you to my Patreon supporters and thank you for Listening

You May Also Like

About the Author: johnwalshonline

Leave a Reply