#Fertility

Groundbreaking demographic research reveals a powerful correlation between America’s declining religiosity and plummeting birth rates, adding crucial cultural dimensions to economic explanations for the nation’s fertility crisis while providing stark warnings for Thailand’s even more severe population challenges. Comprehensive analysis from leading research institutions, including extensive reporting synthesis by major news outlets, detailed demographic studies from the Institute for Family Studies, and new data from the Pew Research Center’s 2023-2024 Religious Landscape Study, demonstrates that highly religious Americans consistently maintain much larger families than their secular counterparts, while the growing population of religiously unaffiliated individuals has dramatically reduced their fertility to levels comparable with the world’s lowest-birth-rate societies. The fertility gap between religious and secular Americans has widened significantly over recent decades, with researchers calculating that virtually the entire decline in U.S. fertility from 2012 to 2019 can be attributed to growing irreligion combined with the exceptionally low birth rates among non-religious populations. Most critically for Thai readers, these findings illuminate how cultural and spiritual institutions provide essential social scaffolding for family formation—scaffolding that Thailand has been rapidly losing through urbanization, secularization, and changing social values, contributing to the kingdom’s catastrophic fertility decline that now threatens long-term economic stability and intergenerational support systems.

A growing body of demographic research finds a clear association between declining religiosity in the United States and the nation’s falling birth rate, adding a cultural dimension to well-known economic explanations for fewer children. Recent reporting and data syntheses – notably a long-form piece in Newsweek summarizing experts’ views, a detailed demographic analysis posted by the Institute for Family Studies, and new estimates from the Pew Research Center’s 2023–24 Religious Landscape Study – show that Americans who are more religious tend to have larger families, while the religiously unaffiliated have had markedly fewer children in recent decades. At the same time, the number of people who identify as nonreligious has grown, meaning the fertility gap by religion now helps explain a meaningful share of the overall decline in U.S. births. These trends matter to Thailand because Thai fertility has fallen even more rapidly, and understanding cultural as well as economic drivers can help shape policies to stabilise family formation and cushion the social effects of population ageing. See the Pew report here, the Institute for Family Studies analysis here, and the CDC’s 2023 birth data here.

The growing reluctance among millennials to have more than two children has emerged as a defining demographic trend, with new research highlighting the complex social and economic factors influencing modern family size decisions. This movement, closely linked to rising living costs and shifting values, carries important implications for Thailand as its own birthrate stagnates and younger generations reconsider their priorities.

A recent report by Business Insider details how economic uncertainty—notably high childcare costs, student debt, and the shaky job market—has led many millennials in developed countries to cap their families at two children or forego parenthood entirely. Drawing from interviews with parents and leading sociologists, the article illustrates how families struggle to afford additional children, especially in expensive urban centers. According to a cited Pew Research Center study, millennial women average about 2.02 children, aligning with earlier generations numerically but diverging in terms of economic stability and timing. Experts argue that for many in this cohort, achieving even a two-child household often feels like a luxury rather than a default lifestyle (businessinsider.com).

The global decline in birth rates, long framed in terms of morality and cultural anxieties by right-wing commentators, is being recast by recent research as a problem rooted overwhelmingly in financial insecurity and systemic economic barriers. According to a groundbreaking United Nations Population Fund (UNFPA) survey, the majority of people worldwide—including Thais—are having fewer children than they desire, primarily because of economic limitations, rather than a loss of interest in family or cultural shifts decried by conservative voices. This pushback comes amid rising alarmism in Western media declaring a “birth-rate crisis” with disastrous economic and social consequences if not urgently addressed.

A new wave of attention is focusing on finasteride, a prescription drug widely used by men worldwide to combat male-pattern baldness, after recent reports and research have highlighted a potential but underrecognized side effect: reduced fertility. For many men, the prospect of restoring hair growth via a daily tablet brings a significant boost of self-esteem. Yet for a minority, this medical fix may temporarily complicate their efforts to start a family, notably by lowering sperm counts—sometimes drastically.

Tiny plastic particles, no wider than a human hair, have made their way into an alarming new corner of human biology: the fluids surrounding eggs in women and sperm in men. The latest research, unveiled at the 2025 European Society of Human Reproduction and Embryology conference and published in the journal Human Reproduction, provides the clearest evidence yet of microplastics’ persistent ability to infiltrate the most sensitive aspects of our bodies—raising serious questions about fertility, long-term health, and the true cost of our reliance on plastics (Earth.com; CNN).

A recent study has detected microplastics in the reproductive fluids of both men and women, sparking global discussion about the potential consequences for fertility and reproductive health. Presented at the 41st Annual Meeting of the European Society of Human Reproduction and Embryology (ESHRE), this research represents one of the first times microplastic contamination has been systematically documented in ovarian follicular fluid and semen, shifting the spotlight from environmental and dietary exposure toward intimate human biological systems. The findings urge both the scientific community and the public to reflect on the far-reaching impact of plastic pollution and what it could mean for future generations, including here in Thailand.

Sperm, the key driver of human reproduction, has fascinated scientists for almost 350 years—yet much about this microscopic “explorer” remains tantalisingly unclear and continues to confound researchers even today. Despite their crucial role in the survival of humanity, recent research reveals that sperm is far more mysterious and complex than once believed, leaving many fundamental questions unanswered and opening new frontiers for scientific inquiry.

For Thai readers, whose concerns span from personal fertility to national demographic trends, the continuing enigma of sperm research is not just a matter for scientific curiosity—it touches on health, society, and the future wellbeing of families across the nation. The paradox is striking: even as advances have been made in reproductive technologies such as IVF and fertility treatments, global evidence indicates that sperm counts are on a worrying decline, and male infertility remains unexplained in the majority of cases, according to the World Health Organization (WHO, 2023).

The United Nations has sounded the alarm on an “unprecedented” worldwide decline in fertility rates, with profound consequences already shaping the future of nations like Thailand. The latest United Nations Population Fund (UNFPA) report signals a tipping point: hundreds of millions of people worldwide are having fewer children than they would like, often citing rising financial pressures and shifting social dynamics as key barriers. For Thailand—a country at the heart of regional demographic shifts—the findings carry urgent weight, offering both fresh validation of local experiences and serving as a catalyst for renewed policy action.

Fears of humanity’s extinction may sound far-fetched, but scientists are warning that global birth rates are falling so fast, some populations could eventually disappear unless women have more children. According to recent research synthesized by experts and highlighted in a much-discussed feature on population trends, the world could see dozens of countries’ populations shrinking by 2100 due to persistently low fertility rates—a phenomenon with profound implications for economies, societies, and the future of human civilization itself (Daily Mail).

A groundbreaking new study has found that adults who report avoidant attachment to their parents are significantly more likely to choose a childfree lifestyle, a trend that is increasingly visible in both Western societies and emerging in Thai urban areas. The research, which analyzes psychological factors influencing reproductive decisions, adds valuable context to ongoing discussions about declining birth rates and shifting family expectations worldwide.

As Thailand faces an alarming drop in national birth rates — the lowest in decades according to the National Economic and Social Development Council (Bangkok Post) — the findings are particularly relevant. While economic uncertainties and shifting societal roles have been widely acknowledged as drivers, the new study highlights the impact of family attachments and early-life emotional bonds on adult choices to remain childfree.

A mild cramp or a touch of fatigue might seem like an everyday nuisance, but new research highlights that dismissing these subtle signs could have serious long-term effects on women’s fertility. Pelvic Inflammatory Disease (PID)—an often silent and preventable disorder affecting the female reproductive system—remains one of the leading causes of infertility, yet public awareness in Thailand and around the globe is worryingly low (Rolling Out).

This news has wide significance for Thai readers, as reproductive health is intrinsically bound not only to personal wellbeing but also broader demographic trends and social stability. While Thailand has made progress in expanding access to reproductive healthcare, conditions like PID—often overshadowed by more high-profile women’s health issues—have a hidden toll, affecting families, livelihoods, and the nation’s future. According to the Department of Obstetrics and Gynecology at Chiang Mai University, PID is frequently underdiagnosed in Thailand because of its subtle presentation and the stigma around sexual health conversations (med.cmu.ac.th).

A sweeping purge of staff at the US Department of Health and Human Services’ (HHS) Division of Reproductive Health has ignited alarm among public health experts, advocates, and former officials, amid fears that the essential infrastructure supporting maternal, infant, and fertility care is now in jeopardy. More than 100 employees were abruptly dismissed this week, gutting teams mandated by federal law to collect and analyze data critical to healthy pregnancies, maternal outcomes, and assisted reproduction—including in vitro fertilization (IVF) support—according to multiple former staffers interviewed by Mother Jones (source).

A growing body of research and expert opinion is highlighting a silent yet serious consequence of excessive abdominal fat in men: a dramatic impact on hormonal balance, sexual health, and fertility. As obesity rates continue to rise—across the world and notably in Asian countries including Thailand—doctors are warning that belly fat is much more than a cosmetic concern. Landmark findings discussed by leading endocrinologists reveal that fat surrounding the waistline acts as an endocrine organ, disrupting testosterone levels and overall male vitality (The News).

Sexually transmitted infections (STIs) are fast emerging as one of the most serious yet often overlooked threats to women’s health and fertility globally, according to the latest research highlighted by experts. Mounting evidence indicates that untreated STIs not only cause acute symptoms but can lead to long-term reproductive health complications, with grave implications for women across all regions—including Thailand.

Recent research reviewed by international health authorities reveals an alarming surge in the incidence of common STIs, such as chlamydia, gonorrhea, and syphilis. These infections, when left untreated, can progress silently to cause pelvic inflammatory disease (PID) and subsequent infertility, especially among women of reproductive age. According to a 2024 review in Drug Topics, millions of women each year are at risk of permanent reproductive harm due to preventable and treatable infections.

Concerns about men’s reproductive health are spurring a wave of recent research, with studies confirming that male fertility has become a significant public health issue worldwide, including in Thailand. New findings reveal that sperm health is highly sensitive to lifestyle, metabolic health, and even infectious diseases like COVID-19, underscoring the urgent need for greater awareness and proactive measures among Thai men and their families.

For decades, discussion around infertility has focused disproportionately on women. Yet, male factors are implicated in nearly half of all infertility cases, according to global health experts and major clinics such as Banner Health in the United States. New research reviewed by leading Australian reproductive health experts has revealed that male sperm counts worldwide have halved since the 1980s—a phenomenon attributed to complex, multifactorial causes that are only now being unraveled (Banner Health).

Recent research is drawing unexpected parallels between the reproductive lives of seals and the challenges facing human fertility, sparking fresh conversations about the hidden environmental factors impacting reproductive health worldwide. As reported in a feature by Oceanographic Magazine, scientists are turning their attention to seals — charismatic marine mammals that live far from hospitals and clinics — in hopes of unraveling why fertility rates are declining across species, including humans (Oceanographic Magazine).

Secondary infertility, a condition where couples struggle to conceive after successfully having had at least one child, is becoming an increasing concern among families worldwide, including here in Thailand. Recent reports and new research highlight not only a steady rise in cases but also the typically overlooked emotional turmoil experienced by affected parents—an issue that has resonated with many Thai families amid shifting demographics and social expectations.

The significance of this trend is well-captured by the candid story of Charlotte Bennett, as reported in The Times. Bennett, already a mother, described the “horrendous” guilt of being unable to give her six-year-old son a sibling, despite years of effort. For many parents, secondary infertility brings an unexpected and deeply personal form of distress, often complicated by cultural expectations and misconceptions that once a couple has had one child, further pregnancies should be easy and natural (The Times).

As more Thai couples and individuals consider starting families later in life, questions about fertility—especially egg quality—are on the rise. Popular wisdom and online advice often tout lifestyle tweaks, diets, or supplements as the magic keys to improving fertility. But does the science back up these claims? According to a comprehensive review of recent research, including a widely cited article from SELF and several new studies in 2024, the answer is nuanced. While age remains the single most influential factor, certain everyday habits may indeed nudge the odds—though not as much as many would hope.

A century-old mystery in female anatomy is being rewritten by new scientific findings: the rete ovarii, long dismissed as a vestigial and “useless” organ, may play a critical role in ovarian function and fertility. This revelation comes from a pioneering mouse study published in March 2025 in the journal eLife, which suggests that this overlooked structure is not only active but potentially essential for reproductive health (Live Science).

The discovery is especially significant for Thai readers, where women’s health issues, particularly regarding fertility and reproductive well-being, remain top concerns for many families and the medical community. For generations, biology textbooks and medical curricula worldwide—including those in Thailand—have listed the ovaries, uterus, and fallopian tubes as the primary organs of the female reproductive tract. The new research now puts the rete ovarii (RO) on the map, suggesting it should be investigated as an additional component crucial to female reproductive function.