Researchers discover how DNA impacts reproductive health and life expectancy

Human reproduction is influenced by a complex interplay of biology, genetics, and socioeconomic factors. Over the past few decades, substantial changes have occurred in reproductive trends across high-income countries.

People are now delaying childbirth, often having their first child at or after age 30. Fertility declines as people get older, and birth intervals between children have lengthened, with some parents having additional children past age 40.

At the same time, lifetime infertility is rising. Globally, around 17.5% of people experience infertility, meaning one in six couples struggle to conceive. Childlessness is increasing as well, driven both by voluntary decisions and involuntary infertility.

For example, 20% of women born in 1965 remained childless by the end of their reproductive years. In Japan, this figure rose to 28% for women born a decade later. Finnish men face similar challenges; one-third of those born between 1969 and 1971 had no children by age 40. Economic pressures, shifting gender roles, and limited access to childcare are among the key drivers of these changes.

However, alongside these social and economic factors, genetic research reveals new insights into fertility and reproductive health. Recent studies show that nearly 50% of infertility cases can be traced to genetic causes. Genetic traits influence when menstruation begins, when menopause occurs, and how many children people are likely to have.

Researchers from the University of Oxford and the University of Iceland analyzed genetic data from 159 studies, identifying 37 genes tied to reproductive traits. Their findings highlight the profound link between DNA, fertility, and broader health outcomes.

One of the most significant discoveries is the role of the FSHB gene. This gene regulates follicle-stimulating hormone, which controls menstruation and menopause. FSHB is associated with 11 different reproductive traits, including the timing of puberty and fertility decline. The gene’s influence doesn’t stop there; it connects reproductive health to conditions such as obesity, hormone-sensitive cancers, and even psychiatric traits.

Lead author Professor Melinda Mills from the Leverhulme Centre for Demographic Science emphasized the importance of understanding these genetic factors, particularly as more people delay parenthood. “Our study brings together research on the genetics of reproduction to reveal common genes across traits and insights beyond fertility,” she explained. “These are inherently linked to health, BMI, obesity, and other key outcomes.”

Other genes, like ESR1 (estrogen receptor 1), reveal how reproductive health connects to longevity and cancer risk. Traits such as early puberty or late menopause, for example, can increase the risk of breast cancer while also being linked to longer lifespans.

Similarly, the FTO gene, already known for its role in obesity and type 2 diabetes, was found to influence reproductive traits. These discoveries show that genetic links between reproduction and overall health are far more intricate than previously understood.

Male fertility, often under-studied, was another focus of this research. Genes like DNAH2 play essential roles in testosterone regulation and sperm function. Co-author Vincent Straub, a researcher at the Leverhulme Centre, stressed the importance of exploring male reproductive genetics. “Male reproductive health is critical to overall fertility but often under-researched,” he said. “By understanding the genetics of male infertility, we can uncover new treatments and insights for those facing reproductive challenges.”

The study also examined how reproductive genes affect future generations. As parents age, they accumulate spontaneous genetic changes known as de novo mutations. These mutations, which can be passed to offspring, may influence the health and development of children. Professor Augustine Kong, a co-author of the review, previously demonstrated the significant role these mutations play in shaping the next generation’s genetic makeup.

The findings have broad implications. Genetic research not only helps explain why reproductive traits differ among individuals but also links fertility to overall health, longevity, and disease risk. For example, while later menopause may boost lifespan, it also raises the chances of developing certain cancers. Conversely, early menopause shortens the reproductive window but can protect against those same conditions.

Understanding the genetics of reproduction could lead to significant advances in personalized medicine. By identifying individuals at higher risk of infertility or related health issues, healthcare providers may offer tailored interventions to improve outcomes.

Dr. Stefanía Benónísdóttir, a lead researcher on the study, underscored this point: “By consolidating this research, we offer a clearer picture of how genetic factors shape reproductive health. This is essential for advancing healthcare, especially when it comes to infertility and reproductive aging.”

These discoveries come at a critical time. As societal trends push childbirth to later ages, genetic factors play a more prominent role in fertility outcomes. Many individuals delay parenthood due to career demands, economic challenges, or personal preferences. However, this shift can exacerbate fertility issues, particularly for those already predisposed to genetic challenges.

The review also highlights how reproductive health intertwines with lifestyle and environmental factors. Conditions like obesity, often influenced by genetics, can disrupt hormone levels and reduce fertility. Likewise, diseases such as diabetes or endometriosis, which have genetic underpinnings, further complicate reproductive outcomes. Addressing these challenges requires a holistic approach that combines genetic insights with medical interventions and public health strategies.

By unraveling the genetic basis of fertility, scientists are laying the groundwork for transformative changes in reproductive healthcare. From better treatments for infertility to enhanced understanding of genetic risks, this research paves the way for healthier outcomes across generations. It also sheds light on how reproduction connects to larger health issues, including cancer, obesity, and aging.

As researchers continue to explore these genetic connections, their findings offer hope for individuals and families facing reproductive challenges. By bridging genetics, health, and society, this work not only deepens our understanding of human reproduction but also opens new pathways for improving lives.

Note: Materials provided above by The Brighter Side of News. Content may be edited for style and length.

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