The World Health Organization defines infertility as a disease of the reproductive system, characterized by the failure to achieve a pregnancy after 12 months or more of regular unprotected sexual intercourse. This classification, aligned with the International Classification of Diseases (ICD-11), applies to both male and female infertility. Globally, about 1 in 6 adults are affected.
How the WHO Defines Infertility
The 12-month threshold is the key benchmark. If a couple has been having regular, unprotected sex for a year without conceiving, the WHO considers that infertility. It’s not a lifestyle issue or a matter of timing. The WHO classifies it as a disease, placing it in the same category as other recognized medical conditions of the reproductive system.
The WHO also distinguishes between two types. Primary infertility means a person has never achieved a pregnancy. Secondary infertility means someone who has previously conceived is now unable to do so again. Both are medically recognized, and both can affect men and women.
How Common Infertility Is Worldwide
In April 2023, the WHO published a landmark report analyzing studies from 1990 to 2021. The headline finding: roughly 17.5% of the adult population worldwide experiences infertility at some point in their lives. That translates to more than 80 million people globally.
One of the most striking details in the report is how consistent the numbers are across income levels. Lifetime prevalence was 17.8% in high-income countries and 16.5% in low- and middle-income countries. Infertility is not concentrated in wealthier nations with later childbearing, as many people assume. It affects populations everywhere at similar rates.
Regional patterns do vary, though. A 2025 analysis of data from 204 countries found that East Asia and Eastern Europe had the highest rates of female infertility, while Australasia (Australia and New Zealand) had the lowest. Central Sub-Saharan Africa and Oceania also showed relatively high prevalence. These differences likely reflect a mix of environmental exposures, infection rates, and access to reproductive healthcare rather than any single cause.
Causes in Women and Men
Infertility is roughly split between male and female factors, with a significant portion of cases involving both partners or remaining unexplained. In women, the most common causes involve problems with ovulation (the release of an egg each month), blocked or damaged fallopian tubes, and conditions like endometriosis or polycystic ovary syndrome. Age plays a major role: egg quality and quantity decline steadily after the mid-30s.
In men, the most common issues are low sperm count, poor sperm movement, or abnormal sperm shape. Hormonal imbalances, undescended testicles, varicoceles (swollen veins in the scrotum), and past infections can all contribute. Lifestyle factors like smoking, heavy alcohol use, and obesity affect fertility in both sexes.
In about 10 to 30% of cases, no clear cause is found in either partner. This is called unexplained infertility, and it can be one of the most frustrating diagnoses to receive because there’s no obvious problem to fix.
The Emotional Weight of Infertility
The WHO frames infertility as a biomedical condition, but the lived experience goes far beyond the physical. Research consistently shows that infertility triggers a cycle of hope and disappointment that takes a serious psychological toll. Fear, anxiety, grief, depression, and a deep sense of helplessness are all commonly reported, particularly among women undergoing treatment.
In many cultures, the ability to have children is closely tied to social identity and family stability. When conception doesn’t happen, people often face stigma, strained relationships, and isolation. Women in particular may feel their standing within the family or community is diminished. These pressures are especially intense in societies where parenthood is seen as a central life role.
Fertility treatments themselves can add to the strain. The repeated cycles of medication, procedures, waiting, and uncertain outcomes create what researchers describe as a “double-edged sword,” offering hope while simultaneously generating new sources of stress, financial pressure, and moral complexity. Yet most fertility clinics focus almost entirely on the physical side, with little structured support for the emotional consequences.
What the WHO Recommends for Fertility Care
In 2023, the WHO released its first comprehensive guideline for the prevention, diagnosis, and treatment of infertility. The central message: fertility care should be accessible to everyone, not just those who can afford private clinics. The guidelines are designed as a framework that individual countries can adopt or adapt into their own national health policies.
The WHO’s position is that wide gaps exist in who can actually access fertility care. In many countries, treatments like assisted reproduction are available only to those with significant financial resources. In others, fertility services barely exist at all. The guidelines push for integration of fertility care into national health systems so that geography and income don’t determine whether someone can seek help. This includes not just medical treatment but also counseling and psychosocial support, acknowledging that infertility affects mental health as much as physical health.