I expect for most of you the answer is no. But we should have. And certainly for any woman over the age of 40 with unexplained infertility, recurrent miscarriage or having had several failed IVF attempts, you absolutely should have heard of it. 

In this article we discuss the affects of chromosomal abnormalities on pregnancy outcomes and whether preimplantation genetic screening or karyotyping is worth it. Spoiler alert: The short answer is, yes! 

So what’s a balanced translocation and where does it come from? 
It’s a genetic condition whereby parts of a chromosome have broken off and attached to other chromosomes in another location. In other words, sections of two chromosomes have switched places. It can be entirely harmless or entirely serious depending on which chromosomes have attached where. 

You might have a chromosomal abnormality affecting the egg or the sperm and it is thought that “50 -75% of spontaneous miscarriages result from numerical chromosomal abnormalities in the embryo or foetus.” (Fritz & Speroff)     

Does age matter? 
Yes. “Data derived from numerous studies reveal that older women and women with a history of recurrent pregnancy loss produce more aneuploid embryos than younger women”. (Fritz & Speroff) 

Is it common? 
Balanced translocations are relatively common, a 2-7% finding among infertile couples. It can affect the man or woman or both - making it a condition we really ought to know more about. (Ching, 2012)

How can we find out if we have it?
Preimplantation genetic screening (PGS) is a relatively new diagnostic and one in which most UK fertility clinics know little about, let alone offer it as a service. 

It is used as an adjunct to IVF whereby the blastocysts are screened for chromosomal abnormalities before being transferred. Generally speaking, half of the blastocysts will be discarded leaving behind the sound ones for implantation. 

If you are unable to garner any blastocysts for PGS you can have karyotyping which involves taking blood samples from both parents which are then examined for chromosome arrangement. 

So why aren’t we told? 
When it comes to fertility, most clinics still like to use the classic ‘get out of jail free’ card - The more attempts at IVF you have, the bigger the chance that one will stick. And it’s true. Even with balanced translocation there’s a chance that one or more blastocysts will still be viable for pregnancy. But the ‘get out of jail free’ card doesn’t take into account the financial and more importantly, emotional toll that multiple failed IVF attempts and/or pregnancy losses have on a person. 

But in order to give a more well-rounded argument the official line is this: “IVF with pre-implantation genetic diagnosis for reasons of advanced maternal age or in couples with unexplained recurrent pregnancy loss can increase implantation rates and decrease miscarriage risk, but have not increased live birth rates. Consequently, the associated costs in couples without other specific indications for IVF cannot be justified.” (Fritz & Speroff) 

Cost aside, wouldn’t knowing that there is a reason for your infertility justify the diagnostic? This is why I strive to explain “unexplained infertility”. It can all be explained with the right diagnostic. And with an explanation, patients are more informed to make decisions over their own fertile future. If the odds are stacked against them and all diagnostics are not pointing in their favour then it might be time to opt for an egg or sperm donor. However for most, the option of donated eggs is presented at a time when they’re at a loss to know what to do next. It then becomes an agonising decision to give up on their own biological children in the quest for a child altogether. It is my belief that, presented with all the facts, a couple can make an informed decision and probably bypass a lot of the emotional anguish. 

So if you’re interested in any of the above, don’t talk to your fertility consultant. As with all my advice - whether it be sperm DNA fragmentation, a varicocele, an underactive thyroid, a balanced translocation. Their answer will invariably be to throw another IVF at it. So instead let’s get informed. Do your own research and don’t just rely on the ‘experts’. 


Extracts taken from: Clinical Gynaecologic Endocrinology and Infertility (Eighth Edition) by Marc A. Fritz and Leon Speroff

Ching, 2012, Presentation and Treatment of Subfertile Men, National Institutes of Health, 
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3783302/ 

Some fab information here about male infertility from Dr. Paul Turek, a leading innovator in male reproductive health.

With declining sperm counts, diminished ovarian reserves, increasing rates of miscarriage, and with the prediction from fertility scientists that all couples will need IVF by the year 2050, protecting our children’s fertility is of paramount importance. Not only so as to shield them from the agony of infertility but also for wider socio-economic reasons. Who will look after the elderly population? 

“Some scientists are now suggesting that the detrimental effects on human reproduction, and the underlying factors contributing to them, could threaten the survival of the human race… an argument could be made that Homo sapiens already fit the standard for an endangered species, based on the US Fish and Wildlife Service’s (FWS) requirements. Of five possible criteria for what makes a species endangered, only one needs to be met; the current state of affairs for humans meets at least three.” (Swan, 2020)

So where does it all begin? The egg of course! But I suppose we’d better not forget the sperm too. Both of which are dictated by the quality of your mother’s and father’s egg and sperm quality, which was dictated by theirs and so on and so forth. 

Next there’s what happens in utero. If babies are subjected to phthalates (plastics) and other chemicals it increases infertility in both girl and boy babies. (Please see my article entitled “Can you predict your fertility?” if you’re interested in this subject.) 

Then there’s what happens at 38 weeks of pregnancy where a huge transfer of antibodies takes place from mother to baby via the placenta. (Cederqvist et al, 1978) Interestingly this is something that happens specifically to humans. 

Then there’s the birth. C-section or vaginal delivery? "Caesarean section use is growing at an “alarming” rate, accounting for 21% of births globally in 2015—up from 12% in 2000—experts have warned.” (Wise, BMJ, 2018) In the UK, one in four babies will be born via c-section according to NHS England. 

To be born is also to enter the world of microbes. “At the very time when the baby is getting out of the mother’s body, its digestive tract and all its mucous membranes are germ-free. Some hours later, there will be billions of germs in its nose, in its mouth and in its gut. The main question is which germs will be the first to colonise the baby’s body?” Will it be those of the mother, or will it be those of the staff in the operating theatre? Will they be friendly and familiar to the baby, or will they be foreign? From a bacteriological point of view there is an inherent and fundamental difference between a vaginal birth and a caesarian birth and the growing number of c-sections has been offered as an explanation for the increasing problem of allergies and food intolerances. (Odent, The Caesarian, 2004) “Children born by cesarean section have been shown to be at higher risk for some immune related disorders.” (Schulfer & Blaser, Risks of Antibiotic Exposures Early in Life on the Developing Microbiome, 2015) 

Then there’s colostrum and breast milk. We of course need not explain how important colostrum and breast milk are at helping to populate the baby’s gut with maternal antibodies known as IgG. And you might feel that provided a baby get to the breast quickly, despite of how they arrived into the world, that they will have adequate IgG. However, the same hormone that is produced in natural labour - oxytocin, which comes in waves during contractions - is also necessary for the contraction of the breast during the milk ejection reflex, when the baby is sucking. Oxytocin must be released through frequent pulsations in order to be effective. A Swedish study “found that two days after birth, when the baby is at the breast, women who gave birth vaginally released oxytocin in a very pulsatile - and therefore effective - way, compared with women who gave birth by emergency caesarian section.” (Odent, 2004) 

Then there’s vaccinations. Some have postulated that the mumps vaccine may be responsible for failing sperm counts. People were vaccinated on mass for mumps virus from the 1970s and so this would correlate with the decline in sperm counts. Of course, this hasn’t been widely researched. No scientist is likely to go near such a controversial hot potato! Not to mention who would fund the research?!

So, taking all these factors into account, it is the immune system that is directly affected. The immune system is in place to protect us from bacterias, viruses, fungus spores and cancer cells but it can make mistakes. It can turn the gun on itself and destroy the very cells it should be protecting. This is what is meant by ‘auto immune disease’. It can also overreact to foreign pathogens who are not really dangerous. This is what is meant by ‘allergy’. 

“Immunologists have to be convinced of the truth that life is a struggle and that struggling is a need, The immune system learns how to fight by fighting. But if the immune system does not get the chance to fight off certain viruses which usually attack in childhood, then it is a much more difficult and exhausting battle as an adult.” (Odent, Primal Health, 2002)  The rush to give a child Calpol to help them sleep at the first sign of a sniffle equates to not giving the immune system a chance to learn how to fight. This is why doctors are nowadays so reluctant to give children antibiotics. We also know that antibiotic exposure within the first 6 months of life significantly increases the child’s body mass for the first 7 years of life. (Tresande, et al, Infant antibiotic exposures and early-life body mass, 2013) With some researchers suggesting that a child’s DNA is significantly changed if given antibiotics in the first year of life. 

The immune system needs to be subjected to the viruses, bacteria and fungi in the early years, so living in a sanitary environment is not conducive to a healthy immune system in adulthood. And there have been many studies showing that children living with dogs or cats have healthier immune systems, simply because of the outdoor bacteria their pet is bringing in. 

So why are our immune systems so important in fertility? Let’s list some auto-immune conditions: 
PCOS, endometriosis, premature ovarian failure, ovarian cancer, breast cancer, cervical cancer, testicular cancer, diabetes, hypothyroidism, lupus, raised natural killer (NK) cells.

So with all this mind I hear you saying, “what can be done?” Well of course some of this is out of your control. You can’t go back in time and knock that drink out of your dad’s hand before he conceived you, or press the stop button when your mum microwaved her TV dinner in plastic at 8 weeks of pregnancy. You can of course try to live healthy lives before you conceive your children. And mums can minimise the risk of exposure to EDCs in utero by eradicating the chemicals that she can from her life; buy organic beauty products and natural cleaning products, get an air purifier, and limit her exposure to plastics, pesticides and fungicides. 

But what about all those emergency c-sections that are out of your control? Vaginal seeding anyone? Sounds delicious doesn’t it. But essentially this is a great workaround to exposing your baby to some of your gut flora. Essentially a swab is inserted in the vagina and then wiped over the baby’s nose and mouth after delivery. Put it on your birth plans people! 

There are many ways we can nurture a strong immune system. Allow your children to bury their heads into as many farmyard animals as possible… that’s an easy one! But also let them get ill. Don’t medicate at the first sign of trouble but allow their immune systems to learn how to fight illness on their own. Let medication be a “fall-back” rather than a “go-to”. 

And lastly, talk to them about infertility. Raise their awareness that fertility is in a dramatic state of decline. And practically, if you have daughters you might want to think about private medical insurance that covers them for gynaecological and fertility problems before they hit puberty so that they may have access to necessary diagnostics and surgery if they need it. Or if you have boys, talk to them about freezing their sperm to be used later in life. You might think this is bonkers but we know that the need for IVF is very much on the rise. You can radically improve the outcome of that IVF by using younger, more potent sperm. (A man is most fertile between the ages of 21 to 25). Wouldn’t it be wonderful if your sons knew they literally had it in the bank! 

References:
Swan, Countdown: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperilling the Future of the Human Race, 2020

Cederqvist LL, Ewool LC, Litwin SD. The effect of foetal age, birth weight, and sex on cord blood immunoglobulin values. Am J Obstet Gynaecol 1978 Jul 1; 131(5): 520-5

Odent, The Caesarian, 2004

Schulfer & Blaser, Risks of Antibiotic Exposures Early in Life on the Developing Microbiome, 2015
(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4489621/)

Odent, Primal Health, 2002

Tresande et al, PubMed, Infant antibiotic exposures and early-life body mass, 2012 Aug 21,
(https://pubmed.ncbi.nlm.nih.gov/22907693/)

Like most of you I’ve been trying to forget about Covid. But I came across some research in recent weeks that has really got me thinking about the pandemic and more to the point, the measures in place to control it. 

This little piece of research has implications that are so far reaching that I felt compelled to share it with you all. 

In a mouse study, mice were infected with SARS-CoV2 infection or COVID-19 and were given Oxytocin (love hormone). The mice not only recovered from the infection quickly but found that it offered them protection from the virus. “Oxytocin has now emerged as a strong candidate for treatment and prevention of the COVID-19 pandemic.” 
Let's focus on the wonderfulness of this for a moment, before we jump to feelings of ‘why the hell were we all starved of seeing our loved ones for so long?’. Maybe love really does conquer all? In my musings I wonder “did Covid become so prevalent because there seems to be so little love in the world?” And then, because my brain is hard wired to jump to fertility it got me thinking about all those pregnant women who need to be induced because they don’t have enough oxytocin to get the show on the road, let alone to deliver the afterbirth. “1 in 3 women in the UK now need to be induced, an increase from 1 in 5 ten years ago.” And of those 2 of 3 women that go into labour naturally only a very small fraction will deliver the placenta without the need for an injection of Syntocinon - synthetic oxytocin. This is standard practice and unless it is specifically stated on your birthing plan that you do not wish for it you will have been given Syntocinon as a matter of course. So the amount of women who can legitimately say they gave birth “naturally” are very few indeed! 

Not only is Oxytocin (OXT) a powerful hormone in pregnancy it has so many other health benefits. “OXT can block viral invasion, suppress cytokine storm, reverse lymphocytopenia, and prevent progression to ARDS and multiple organ failures. Importantly, besides prevention of metabolic disorders associated with atherosclerosis and diabetes mellitus, OXT can protect the heart and vasculature through suppressing hypertension and brain-heart syndrome, and promoting regeneration of injured cardiomyocytes. Unlike other therapeutic agents, exogenous OXT can be used safely without the side-effects seen in remdesivir and corticosteroid. Importantly, OXT can be mobilized endogenously to prevent pathogenesis of COVID-19.”

We knew that oxytocin was important in the fight against cold viruses back in 2014. A study group of 404 healthy adults were intentionally infected with flu virus and were asked how often they received hugs from a trusted person during their illness. "Among infected participants, greater perceived social support and more frequent hugs both resulted in less severe illness symptoms”.
​
So there you have it… All you need is love. And to never be locked down and socially distanced again! 

Wang & Wang, Cardiovascular protective properties of oxytocin against COVID-19, April 1 2021, (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7837104/ )

Rise in women having induced labours, NHS figures show, BBC News, 2018 (https://www.bbc.co.uk/news/health-45978623)
​
Hugs Help Protect Against Stress and Infection, Say Carnegie Mellon Researchers, December 2014 (https://www.cmu.edu/news/stories/archives/2014/december/december17_hugsprotect.html)

A very interesting discussion surrounding the research to date. Worth a watch!

I wonder how many of us have done some DIY palmistry to predict how many children we’ll have? Apparently it’s the amount of vertical lines under your little finger. I wonder how many of you are checking that now?

But what if I told you there’s another way to predict your fertility that is fully endorsed by modern science. Anogenital distance (AGD) is the measurement between the anus and base of penis in a man, or anus and clitoris in a woman and can accurately predict the quality of the semen in men, and in women can show testosterone based hormonal disorders such as PCOS. Anyone ever checked that one before?! I won’t ask how many are checking it now! 

It is such an accurate diagnostic for ascertaining future fertility in boys that some reproductive scientists are asking that it be a standard assessment by midwives. 

The measurement is also a useful tool in adulthood. In men, the shorter the AGD the more likely a person will be to be childless, and/or have sperm insufficiency and pathology. In women, the longer the AGD the more likely they will be to have elevated testosterone diseases such as PCOS. Basically, the longer the AGD the more the testosterone. Great in men! Not so great in women. 

So what determines the AGD? Blame your mothers. “If a woman is exposed to chemicals that block the action of androgens in the first trimester of pregnancy - during what’s called the reproductive programming window - it can affect the reproductive development of the male foetus in numerous ways. One is to shorten the AGD… which correlates with a lower sperm count and a smaller penis.” It can also increase the chance of undescended testicles. Another big problem affecting fertility in males. (Swan, 2020)

The same is true for baby girls. “Evidence suggests that some of the same chemicals that can affect male genital development in the womb can impact the timing of puberty in girls, leading most notably to earlier development of pubic hair, breasts, and the start of a girl’s period. In addition, in utero exposure to some of these same chemical culprits can have a negative impact on a female embryo’s ovarian function, leading to a hastened depletion of eggs when she’s a grown woman and an earlier age of menopause.” (Swan, 2020) 

So which chemicals are causing all the damage? Chemicals known as EDCs (Endocrine Disrupting Chemicals) are the culprits and unfortunately they are virtually impossible to avoid. Pthalates (plastics) are the big ones. Closely followed by Bisphenol A - used to line food cans, piping, receipt paper and other everyday items. Flame retardants used to Scotch Guard carpets and in all sofas, mattresses, etc. Pesticides, including herbicides, insecticides and fungicides. And it doesn’t stop there. There are many other chemical compounds that affect the endocrine system and as new chemicals emerge, it will take years to understand their impact on our reproductive systems. 

DEHP, part of the chemical compound for Bisphenol A, for example, was used in a therapeutic setting in the 1940s to treat menstruation and the menopause as it was considered to be five times more potent than oestrogen. Worse still, it was used to prevent miscarriage and wasn’t banned until 1971 when it was discovered it caused a rare cancer in the women’s daughters. (Swan, 2020)

Unfortunately the substitutes that have come in to replace their predecessors are often as harmful as the ones they’ve been sent in to replace. It just takes years of research to prove and all the while consumers believe it safe. 

So what does this mean for our future generation’s fertility? Well it’s bleak. With the continued decline in sperm health and with no signs of the curve levelling off it is predicted that everyone will need to use IVF to conceive by 2050. 

Swan, 2020, Countdown: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperilling the Future of the Human Race

Eisenberg & Lipshultz, 2015, Anogenital distance as a measure of human male fertility, [Published online Dec 13 2014] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4363236/

Listen to this fantastic podcast of two of my very lovely patients talking all things reciprocal IVF, egg donation and endometrial scratches. Spoiler alert - I get a mention!  *blush*

I’d love to say I’ve read the book. But only because that’s what everyone loves to say! Instead I’ve read a different book and one in which the author shares my growing concerns. Until now I thought I was the only one who was worried by the rapid decline in sperm health, plummeting by 50% over the last 40 years. But finally researchers are starting to piece the evidence together. Professor Shanna Swan, one of the world’s leading environmental and reproductive epidemiologists provides disturbing statistics which makes me question whether The Handmaid’s Tale is not a work of fiction but more a glimpse into the very alarming future. 

For the last few years, while everyone else has been talking about climate change, I’ve been worrying about a different threat. But this one seems to get way less traffic when it comes to the global stage. There’s no Sperm Summit for instance. Yet research shows that sperm health is rapidly declining with no signs of levelling off and it is predicted that by 2050 everyone will need to use assisted reproduction (IVF) to have a baby. 

So how have we dealt with this? Thank goodness for the World Health Organisation who very cleverly stepped in to resolve the problem. In the 1940s the WHO considered an adequate sperm count to be 60 million/mL. In 1980 they lowered this to 20 million/mL and by 2010 it was further reduced to 15 million/mL. Phew! 

By the 1980s they’d figured out what to do. “Male factor infertility is the only medical situation that’s treated by administering a painful procedure to a woman because of a problem that afflicts her male partner.” (Swan) This is in the form of assisted reproduction (AR), which to any who are unfamiliar, involves the woman injecting herself with hormones to stimulate egg production where ovaries swell to the size of grapefruits so that she might ripen anywhere from 5 to 20 eggs (in a natural cycle only 1 to 2 eggs would ripen and release every month). These eggs are extracted under general anaesthetic, mixed with sperm that has been extracted the ‘easy way’, before being implanted back into the woman’s uterus without the use of any anaesthetic at all. They’re told it’s like an “uncomfortable smear”, but for some it’s excruciating. 

You might be under the illusion that this is the only way to make a baby when the sperm isn’t up to scratch and therefore an unfortunate necessity. It’s not. TESA (Testicular Sperm Aspiration) is exactly what it says on the tin. A needle is inserted into the testicles and sperm are aspirated out. Yet despite this radically improving the outcome of AR I have only known two men in my entire career who were willing to have the procedure. “The pregnancy rate using testicular [TESA] and ejaculated [the old fashioned way] spermatozoa was 44% and 6%, respectively.” (Zini & Agarwal) The lack of uptake for men having TESA is in part due to them being unaware it exists. It is not something offered in most fertility clinics despite them having the ability to perform the procedure. To add to this, men are rarely given any dietary, lifestyle or supplementation advice, even if they have a poor sperm assay. Instead women are told to cut out alcohol, reduce their BMI and take pre-conception vitamins when actually obesity and alcohol affect sperm quality far more than in female reproductive health. “Alcohol damages chromatin integrity and increases DNA fragmentation in sperm”. (Zini & Agarwal) Correct supplementation in men is shown to markedly improve overall sperm quality by 48.9% in three months and 80.9% in six months. (Gvozdjáková A et al, 2015) Yet I’m eternally gobsmacked that this type of useful information isn’t disseminated down to the patient. Are we so afraid that men can’t handle the truth? That they might be solely responsible for being unable to start a family and that THEY might want to do something about it. In my experience most men would do a whole lot about it given the information by a medical fertility consultant. I have certainly come across men who have said that if their fertility consultant isn’t bothered by their sperm assay then why should I be? You can imagine my frustration! The fact is the goal posts have been moved. What equates to a “good” sperm result today would be considered exceptionally poor as little as 10 years ago. 

So why do women suffer unnecessarily, take the hormones, go on diets, etc and are totally willing to do whatever it takes? Because the pull for a baby is often far stronger than defending any female rights. Some women will do almost anything to have a baby, and herein lies the problem. It’s not a fault, merely a hormonal and innate urge to procreate and nurture a child. But in this way we can be manipulated into almost anything for the promise of a child. The same can be true of men too. (Of course it’s not just women who suffer.) My point here is that the subject of fertility is emotive and can make people do crazy things.

If you’ve not come round to my way of thinking, that The Handmaid’s Tale might be a prediction of the future, let’s consider what happens with the ageing process and fertility. Up until fairly recently we thought only women had a biological clock but it is clear now that men’s fertility also decreases steadily from age 35 onwards in the form of Sperm DNA Fragmentation. (You can read more about this is my blog article “Could it be Sperm DNA Fragmentation?”) “Studies suggest that for men ages forty and older, their partner has a 60 percent increased risk of experiencing miscarriage, compared to partners under thirty.” (Swan) Young eggs can accommodate older sperm and “make good” sperm that would not be viable if it was paired with an older egg. I predict that as sperm rates decline, younger, fertile women will become a commodity. We’ve already seen this with the rate of surrogacy rising in popularity. Couples seeing their only hope of starting a family by renting a uterus. I understand it. I can see how being unable to have a child can make you do some unorthodox things; I am a fertility acupuncturist after all!

And then, in the television series, there’s the issue of toxins and chemicals having created this unhealthy and infertile environment with barren Handmaid’s being sent to the “colonies” to finish their miserable lives. For anyone who hasn’t seen it this place depicts areas of contaminated, radioactive wasteland. Not too dissimilar to some parts of the UK! Bristol scores particularly high on the air pollution rankings with The Guardian reporting “Air pollution kills five people in Bristol each week, study shows”. (guardian.com) 

Today, the rise in male factor infertility is thought largely to be due to environmental pollutants. Baby boys exposed to high levels of phthalates (found in plastics) in the womb were shown to have diminished fertility in adulthood. The trend continues if the exposure carries on through adulthood. Despite the overwhelming evidence that phthalates (among other chemicals) are responsible for such a downward turn in male fertility they are still widely used. Worse still, chemicals that have been shown to be “harmful” are replaced by chemicals that haven’t been tested and the replacements tend to be no better than their predecessors. “In essence, this takes advantage of the public’s misperception that the replacement is inherently safe.” (Swan) 

In my blog article, Chemical Warfare, I speak about the issues of chemicals affecting our health. “There are around 70,000 to 85,000 chemicals in use today, with around 2,000 new chemicals coming onto the market each year. It is estimated that around 1% of these chemicals have been tested as Environment Protection Agencies struggle to keep up with the growing volume of new chemical compositions.” The fact of the matter is, we know they are not safe, yet we continue to use them as there just isn’t an alternative. What would we do without plastics?! 

So, we know male fertility is rapidly declining. We know this is largely due to environmental exposure to chemicals and toxins that baby boys are exposed to in and outside of the womb. We know that with fewer young people we will not be able to support the older generation. “What will happen in the future - will sperm count reach zero? Is there a chance that this decline would lead to extinction of the human species? Given the extinction of multiple species, associated with man-made environmental disruption, this is certainly possible.” (Levine) 

So realistically, I’m not sure if we’ll ever see the types of tyrannical characters and restrictions we see in The Handmaid’s Tale. But certainly we will see infertility becoming a global problem that will require radical intervention. Indeed male infertility IS a global problem but sssssh… don’t for goodness sake’s tell anyone!

For more information on the subject and to read a fantastic book packed full of research and statistics on the problems we face both in male and female infertility please read: Countdown: How our modern world is threatening sperm counts, altering male and female reproductive development, and imperilling the future of the the human race by Shanna H. Swan, PhD. I highly recommend it. And if you have sons it is your duty to read this book!

https://blackwells.co.uk/bookshop/product/9781982113667?gC=5a105e8b&gclid=CjwKCAjw07qDBhBxEiwA6pPbHqdkoKjL34w-whsCpMYs8SqcrQzxpK_Gim-lM_SXroxCXozirPoI-xoC8ugQAvD_BwE

​References:
Swan, Countdown: How our modern world is threatening sperm counts, altering male and female reproductive development and imperilling the future of the human race, 2020

Zini and Agarwal, A Clinician's Guide to Sperm DNA and Chromatin Damage, 2018

Laville, Air pollution kills five people in Bristol each week, study shows,  18 November 2019, https://www.theguardian.com/environment/2019/nov/18/air-pollution-kills-bristol-health [Accessed on 8th April 2021]