Male infertility crisis

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The male infertility crisis is an increase in male infertility since the mid-1970s. [1] The issue attracted media attention after a 2017 meta-analysis found that sperm counts in Western countries had declined by 52.4 percent between 1973 and 2011. [2] [3] The decline is particularly prevalent in Western countries such as New Zealand, Australia, Europe, and North America. [4] A 2022 meta-analysis reported that this decline extends to non-Western countries, namely those in Asia, Africa, Central America, and South America. [5] This meta-analysis also suggests that the decline in sperm counts may be accelerating. [5]

Contents

This decline in male fertility is the subject of research and debate. Proposed explanations include lifestyle factors, such as changes in diet and physical activity levels, and increased exposure to endocrine disrupting chemicals, such as those found in plastics and pesticides. [6] [7] Some scientists [8] [9] have questioned the extent of the crisis; the scientific community, however, generally acknowledges increasing male infertility as a men's-health issue. [10]

Media coverage and terminology

The term male fertility crisis dates to the 1970s. [11] Increased awareness during the 1990s expanded the scope of research to address social and biological factors. [12] Academia and the scientific community have reached consensus in favor of the use of the term male infertility crisis, citing it as necessary to prompt preventative action to remedy the issue in the present time before it affects future generations on a greater scale. [11] Social commentators have said that the wide-ranging consequences of male infertility necessitate the use of crisis, [13] since widespread involuntary childlessness can be viewed as a crisis. [14]

Research analysis has found that amongst a sample of British newspapers in the 1990s, there was a recognizable discourse about a male fertility crisis. [12] Media coverage increased during the 2010s, often coinciding with (or in response to) releases of studies and using words like "crisis", "apocalypse", "time bomb", and "threat to the human race". The mass-media coverage is controversial, since the use of such terms has led to concern that it has fostered clickbait or hysterical coverage playing on community fears. [11] [15] Media coverage often uses vivid comparisons, such as sperm counts in other animals. [12] The long-term effects of male infertility have been explored in dystopian fiction such as Children of Men and The Handmaid's Tale . [1] [16]

Development and history

1970s–1980s

During the 1970s and 1980s, the first studies were published which observed declines in human semen quality and, later, sperm quantity. One of the earliest studies, published in 1974, noted a reduction in sperm quality (lower sperm concentration and semen volume) and a higher percentage of abnormal sperm. [17] These early studies' methodology has been criticized for sampling bias and the inclusion of men with testicular and fertility issues. [11] Other reports published during the two decades had not found similar declines; a 1982 research paper by Niecheslag et al. concluded that there were no changes in semen quality. [18] The decline in sperm quality reflected a shift in societal patterns of sexual behaviour, widespread recreational drug use, and preferences for marriage and fatherhood later in life. [19]

The World Health Organization published its first laboratory manual for semen analysis in 1980, which sets global standard parameters for the measurement of sperm quality and normality. [20] Limited research in the 1980s found the first indications behind the decline, with links to environmental-toxin exposure and excessive heat in the genital area. [19]

1990s–2000s

The 1990s saw significant development in research on male infertility, with reliable results indicating a decline. A 1992 Danish meta-analysis, commonly known as the Carlsen study after its principal author, showed that between 1938 and 1990 a population described as healthy had experienced a significant decrease in sperm count and semen volume. [21] [22] Following this study, other studies supported this thesis. During the late 1990s, the first studies of the social and psychological impact of male infertility were published. [23] Near the end of the decade, the conception technique of intracytoplasmic sperm injection (ICSI, similar to in vitro fertilisation) was introduced. [24]

2010s–present

By the 2010s, it was clear that there had been a significant, steady decline in sperm count and semen volume. A 2017 meta-analysis led by Hagai Levine from the Hebrew University reported decreases in sperm concentration of 52.4 percent and in sperm count of 59.3 percent, from 1973 to 2011 in Western countries (Australia, New Zealand, Europe, and North America). [25] Two other studies presented at the 2018 American Society for Reproductive Medicine (ASRM) scientific congress had similar findings: reduced sperm counts and motility during the 2000s. [11] A 2012 paper published by French researchers and Yeshiva University's Institute for Public Health Sciences in the Journal of Human Reproduction studied French males from 1989 to 2005 and concluded that sperm counts and the proportion of normal, motile sperm fell by 32.2 and 8.1 percent, respectively. [26] [27]

Mt. Sinai Medical School epidemiologist Shanna Swan wrote in her 2021 book, Count Down: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race, "If you look at the curve on sperm count and project it forward – which is always risky – it reaches zero in 2045". [28]

Another meta-analysis in 2022, again led by Hagai Levine, reported that sperm concentration declined by 53.3 percent and sperm count by 56.3 percent in Western countries (1973-2015), and by 27.6 and 24.7 percent respectively, in non-Western countries (1986-2018). [5] Moreover, when the dataset was restricted to more recent studies (post-2000), the declines in semen parameters became steeper. For instance, the decline in worldwide sperm concentration doubled, suggesting that these declines may be accelerating. [5]

A 2022 review by prominent researchers in the field of human fertility suggested that increasing industrialisation over the 20th century has led to an increase in exposure to endocrine disrupting chemicals, which may have contributed to the decline in sperm counts. [6] Other research published in 2023 has linked the change in diet associated with industrialisation, termed the nutrition transition, to declining sperm counts, estimating that the transition from an unprocessed to modern processed diet may account for up to 30 percent of the decline in sperm counts. [7]

Impacts and responses

Male fertility issues have been overlooked in the past, [29] [30] and fertility research has focused on women. [23] Sociologists studying male infertility have found that awareness has shifted societal attitudes on fertility and gender more toward men. [29]

Believers that male infertility has reached crisis proportions say that more must be done to remediate potential causes of male infertility, such as lifestyle factors and exposure to toxic environmental chemicals. [31] [10] They advocate modernizing health care with improved practices and increased funding. [32]

Social programs to alleviate the impact of the crisis have been implemented as part of men's reproductive health. Events such as International Men's Health Week and Movember advocate reforms to address the crisis. [33] [34]

The Australian federal government funded the Healthy Male, a program to support male reproductive health and fertility, and issued a A$3 million research grant to Andrology Australia. [35] Other national-government responses include recommendations by the UK's National Health Service for a healthy lifestyle and loose-fitting underwear to improve fertility. [36]

Criticism

Critics of labeling male infertility a crisis have cited research which has partially stigmatized men, and say that male infertility has inadvertently been conflated with mental health and social vulnerability. However, no direct evidence supports such stigmatization. [37] Gannon et al. wrote in 2004 that media coverage of the crisis has posed it as a threat to hegemonic masculinity. [12]

Scientists disagree on the impact of observed fertility declines to date, and sperm counts remain above the 15 million considered to be below normal by the World Health Organization. The issue of most concern is reducing average abnormal-sperm counts. [38] Health practitioners and fertility doctors who work in the field are skeptical about a crisis in male fertility, since they had not observed a dramatic decline first-hand; a disconnect exists between what has been observed in published research and what is seen in clinical practice. [39]

It has also been pointed out that sexual and masturbatory cultural shifts may be the true driver of the phenomenon, as more frequent ejaculation quickly reduces sperm counts. [40] [41]

Andrologists have said that not enough research has been conducted on male fertility to address the crisis effectively. [42] Existing treatments, such as assisted reproductive technology, are difficult to access and may have severe complications. [43]

See also

Related Research Articles

<span class="mw-page-title-main">In vitro fertilisation</span> Assisted reproductive technology procedure

In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro. The process involves monitoring and stimulating a woman's ovulatory process, removing an ovum or ova from their ovaries and letting a man's sperm fertilise them in a culture medium in a laboratory. After the fertilised egg (zygote) undergoes embryo culture for 2–6 days, it is transferred by catheter into the uterus, with the intention of establishing a successful pregnancy.

Reproductive technology encompasses all current and anticipated uses of technology in human and animal reproduction, including assisted reproductive technology (ART), contraception and others. It is also termed Assisted Reproductive Technology, where it entails an array of appliances and procedures that enable the realization of safe, improved and healthier reproduction. While this is not true of all people, for an array of married couples, the ability to have children is vital. But through the technology, infertile couples have been provided with options that would allow them to conceive children.

<span class="mw-page-title-main">Infertility</span> Inability to reproduce by natural means

Infertility is the inability of an animal or plant to reproduce by natural means. It is usually not the natural state of a healthy adult, except notably among certain eusocial species. It is the normal state of a human child or other young offspring, because they have not undergone puberty, which is the body's start of reproductive capacity.

Fertility in colloquial terms refers the ability to have offspring. In demographic contexts, fertility refers to the actual production of offspring, rather than the physical capability to reproduce, which is termed fecundity. The fertility rate is the average number of children born during an individual's lifetime. In medicine, fertility refers to the ability to have children, and infertility refers to difficulty in reproducing naturally. In general, infertility or subfertility in humans is defined as not being able to conceive a child after one year of unprotected sex. The antithesis of fertility is infertility, while the antithesis of fecundity is sterility.

Fertility medications, also known as fertility drugs, are medications which enhance reproductive fertility. For women, fertility medication is used to stimulate follicle development of the ovary. There are very few fertility medication options available for men.

<span class="mw-page-title-main">Azoospermia</span> Medical condition of a man whose semen contains no sperm

Azoospermia is the medical condition of a man whose semen contains no sperm. It is associated with male infertility, but many forms are amenable to medical treatment. In humans, azoospermia affects about 1% of the male population and may be seen in up to 20% of male infertility situations in Canada.

Male contraceptives, also known as male birth control, are methods of preventing pregnancy by interrupting the function of sperm. The main forms of male contraception available today are condoms, vasectomy, and withdrawal, which together represented 20% of global contraceptive use in 2019. New forms of male contraception are in clinical and preclinical stages of research and development, but as of 2024, none have reached regulatory approval for widespread use.

Terms oligospermia, oligozoospermia, and low sperm count refer to semen with a low concentration of sperm and is a common finding in male infertility. Often semen with a decreased sperm concentration may also show significant abnormalities in sperm morphology and motility. There has been interest in replacing the descriptive terms used in semen analysis with more quantitative information.

Hypospermia is a condition in which a man has an unusually low ejaculate volume, less than 1.5 mL. It is the opposite of hyperspermia, which is a semen volume of more than 5.5 mL. It should not be confused with oligospermia, which means low sperm count. Normal ejaculate when a man is not drained from prior sex and is suitably aroused is around 1.5–6 mL, although this varies greatly with mood, physical condition, and sexual activity. Of this, around 1% by volume is sperm cells. The U.S.-based National Institutes of Health defines hypospermia as a semen volume lower than 2 mL on at least two semen analyses.

Male infertility refers to a sexually mature male's inability to impregnate a fertile female. In humans, it accounts for 40–50% of infertility. It affects approximately 7% of all men. Male infertility is commonly due to deficiencies in the semen, and semen quality is used as a surrogate measure of male fecundity. More recently, advance sperm analyses that examine intracellular sperm components are being developed.

<span class="mw-page-title-main">Semen quality</span> Measure of male fertility

Semen quality is a measure of male fertility, a measure of the ability of sperm in semen to accomplish fertilization. Semen quality involves both sperm quantity and quality. Semen quality is a major factor for fertility.

<span class="mw-page-title-main">Reproductive toxicity</span> A hazard associated with chemical substances

Reproductive toxicity refers to the potential risk from a given chemical, physical or biologic agent to adversely affect both male and female fertility as well as offspring development. Reproductive toxicants may adversely affect sexual function, ovarian failure, fertility as well as causing developmental toxicity in the offspring. Lowered effective fertility related to reproductive toxicity relates to both male and female effects alike and is reflected in decreased sperm counts, semen quality and ovarian failure.

<span class="mw-page-title-main">Ashok Agarwal</span> Medical Scientist

Ashok Agarwal is the Director of the Andrology Center, and also the Director of Research at the American Center for Reproductive Medicine at Cleveland Clinic, Cleveland, USA. He is Professor at the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, USA. Ashok is a Senior Staff in the Cleveland Clinic's Glickman Urological and Kidney Institute. He has published extensive translational research in human infertility and assisted reproduction.

Obesity is defined as an abnormal accumulation of body fat, usually 20% or more over an individual's ideal body weight. This is often described as a body mass index (BMI) over 30. However, BMI does not account for whether the excess weight is fat or muscle, and is not a measure of body composition. For most people, however, BMI is an indication used worldwide to estimate nutritional status. Obesity is usually the result of consuming more calories than the body needs and not expending that energy by doing exercise. There are genetic causes and hormonal disorders that cause people to gain significant amounts of weight but this is rare. People in the obese category are much more likely to suffer from fertility problems than people of normal healthy weight.

<span class="mw-page-title-main">Globozoospermia</span> Medical condition

Globozoospermia is a rare and severe form of monomorphic teratozoospermia. This means that the spermatozoa show the same abnormality, and over 85% of spermatozoa in sperm have this abnormality. Globozoospermia is responsible for less than 0.1% of male infertility. It is characterised by round-headed spermatozoa without acrosomes, an abnormal nuclear membrane and midpiece defects. Affected males therefore suffer from either reduced fertility or infertility. Studies suggest that globozoospermia can be either total or partial, however it is unclear whether these two forms are variations on the same syndrome, or actually different syndromes.

Antisperm antibodies (ASA) are antibodies produced against sperm antigens.

Robert John Aitken is a British reproductive biologist, widely known for identifying oxidative stress as a significant contribution to infertility and its actions on human sperm function. He also made substantial contributions to clinical practice translation in male reproductive health, notably the development of new contraceptive vaccine.

<span class="mw-page-title-main">Sperm Chromatin Structure Assay</span>

Sperm Chromatin Structure Assay (SCSA) is a diagnostic approach that detects sperm abnormality with a large extent of DNA fragmentation. First described by Evenson in 1980, the assay is a flow cytometric test that detects the vulnerability of sperm DNA to acid-induced denaturation DNA in situ. SCSA measures sperm DNA fragmentation attributed to intrinsic and extrinsic factors and reports the degree of fragmentation in terms of DNA Fragmentation Index (DFI). The use of SCSA expands from evaluation of male infertility and subfertility, toxicology studies and evaluation of quality of laboratory semen samples. Notably, SCSA outcompetes other convention sperm DNA fragmentation (sDF) assays such as TUNEL and COMET in terms of efficiency, objectivity, and repeatability.

<span class="mw-page-title-main">Use of assisted reproductive technology by LGBT people</span>

Lesbian, gay, bisexual, and transgender people people wishing to have children may use assisted reproductive technology. In recent decades, developmental biologists have been researching and developing techniques to facilitate same-sex reproduction.

Shanna Helen Swan is an American environmental and reproductive epidemiologist who is Professor of Environmental Medicine and Public Health at the Icahn School of Medicine at Mount Sinai, where she has taught since April 2011. She is known for her research on environmental contributions to sperm count and the male infertility crisis.

References

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  2. ↑ Levine, Hagai; Jørgensen, Niels; Martino-Andrade, Anderson; Mendiola, Jaime; Weksler-Derri, Dan; Mindlis, Irina; Pinotti, Rachel; Swan, Shanna H (2017-07-25). "Temporal trends in sperm count: a systematic review and meta-regression analysis". Human Reproduction Update. 23 (6): 646–659. doi:10.1093/humupd/dmx022. ISSN   1355-4786. PMC   6455044 . PMID   28981654.
  3. ↑ Davis, Nicola (2017-07-25). "Sperm counts among western men have halved in last 40 years – study". The Guardian. Retrieved 2018-10-10.
  4. ↑ Johnston, Ian (25 July 2017). "Western men's sperm counts plunge 60% in 40 years due to 'modern life'". The Independent. Retrieved 2018-10-10.
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  6. 1 2 Skakkebæk, Niels E.; Lindahl-Jacobsen, Rune; Levine, Hagai; Andersson, Anna-Maria; Jørgensen, Niels; Main, Katharina M.; Lidegaard, Øjvind; Priskorn, Lærke; Holmboe, Stine A.; Bräuner, Elvira V.; Almstrup, Kristian; Franca, Luiz R.; Znaor, Ariana; Kortenkamp, Andreas; Hart, Roger J. (March 2022). "Environmental factors in declining human fertility". Nature Reviews. Endocrinology. 18 (3): 139–157. doi:10.1038/s41574-021-00598-8. ISSN   1759-5037. PMID   34912078.
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  8. ↑ Boulicault, Marion; Perret, Meg; Galka, Jonathan; Borsa, Alex; Gompers, Annika; Reiches, Meredith; Richardson, Sarah (2021-05-10). "The future of sperm: a biovariability framework for understanding global sperm count trends". Human Fertility. 25 (5): 888–902. doi: 10.1080/14647273.2021.1917778 . ISSN   1464-7273. PMID   33969777. S2CID   234344423.
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  11. 1 2 3 4 5 Fetters, Ashley (2018-10-12). "Sperm Counts Continue to Fall". The Atlantic. Retrieved 2020-05-28.
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  23. 1 2 Webb, Russell E.; Daniluk, Judith C. (1999). "The End of the Line: Infertile Men's Experiences of Being Unable to Produce a Child". Men and Masculinities. 2 (1): 6–25. doi:10.1177/1097184X99002001002. ISSN   1097-184X. S2CID   73326269.
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  25. ↑ Levine, Hagai; Jørgensen, Niels; Martino-Andrade, Anderson; Mendiola, Jaime; Weksler-Derri, Dan; Mindlis, Irina; Pinotti, Rachel; Swan, Shanna H. (1 November 2017). "Temporal trends in sperm count: a systematic review and meta-regression analysis". Human Reproduction Update. 23 (6): 646–659. doi:10.1093/humupd/dmx022. ISSN   1460-2369. PMC   6455044 . PMID   28981654.
  26. ↑ "Countdown". The Economist. ISSN   0013-0613 . Retrieved 2020-05-28.
  27. ↑ Rolland, M.; Le Moal, J.; Wagner, V.; Royère, D.; De Mouzon, J. (2013). "Decline in semen concentration and morphology in a sample of 26 609 men close to general population between 1989 and 2005 in France". Human Reproduction. 28 (2): 462–470. doi: 10.1093/humrep/des415 . ISSN   1460-2350. PMC   4042534 . PMID   23213178.
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  29. 1 2 Petok, William D. (2015). "Infertility counseling (or the lack thereof) of the forgotten male partner". Fertility and Sterility. 104 (2): 260–266. doi: 10.1016/j.fertnstert.2015.04.040 . PMID   26048155.
  30. ↑ Ravitsky, Vardit; Kimmins, Sarah (2019-11-21). "The forgotten men: rising rates of male infertility urgently require new approaches for its prevention, diagnosis and treatment". Biology of Reproduction. 101 (5): 872–874. doi:10.1093/biolre/ioz161. ISSN   0006-3363. PMC   6877781 . PMID   31553040.
  31. ↑ Berry, Sarah (2017-07-26). "'We are not in crisis yet': 60 per cent drop in sperm count can be reversed". The Sydney Morning Herald. Retrieved 2020-05-28.
  32. ↑ "Opinion: Impending fertility crisis requires urgent action". Montreal Gazette. Retrieved 2020-05-28.
  33. ↑ "Home". Men's Health Week. Retrieved 2020-05-28.
  34. ↑ "Movember". Movember. Retrieved 2020-05-28.
  35. ↑ "$19.7 million National Men's Health Strategy". Greg Hunt MP. 11 April 2019. Retrieved 2020-05-28.
  36. ↑ "Why tomato puree might improve male fertility". BBC News. 2019-10-09. Retrieved 2020-05-28.
  37. ↑ Hanna, Esmée; Gough, Brendan (2015-12-23). "Experiencing Male Infertility: A Review of the Qualitative Research Literature". SAGE Open. 5 (4): 215824401561031. doi: 10.1177/2158244015610319 . ISSN   2158-2440.
  38. ↑ "expert reaction to meta-analysis of sperm count among men in Western countries | Science Media Centre" . Retrieved 2020-05-28.
  39. ↑ Belluz, Julia (2018-09-17). "Sperm counts are falling. This isn't the reproductive apocalypse — yet". Vox. Retrieved 2020-05-28.
  40. ↑ Menger, H.J. (1994-05-28). "Sexual revolution and sperm count". BMJ (Clinical Research Ed.). 308 (6941): 1440–1441. doi:10.1136/bmj.308.6941.1440b. PMC   2540338 . PMID   8019272.
  41. ↑ Welliver, Charles; Benson, Aaron D.; Frederick, Luke; et al. (2016-10-05). "Analysis of semen parameters during 2 weeks of daily ejaculation: a first in humans study". Translational Andrology and Urology. 5 (5): 749–755. doi: 10.21037/tau.2016.08.20 . PMC   5071206 . PMID   27785432.
  42. ↑ "Tackling the stigma around male infertility". Raconteur. 2018-04-23. Retrieved 2020-05-28.
  43. ↑ Ravitsky, Vardit; Kimmins, Sarah (2019-11-21). "The forgotten men: rising rates of male infertility urgently require new approaches for its prevention, diagnosis and treatment". Biology of Reproduction. 101 (5): 872–874. doi: 10.1093/biolre/ioz161 . ISSN   0006-3363. PMC   6877781 . PMID   31553040.
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