It's a frequent misconception that identical twins share fingerprints. Each twin has a unique set of fingerprints that convey a different tale, despite the fact that they may appear remarkably alike and share a lot of DNA.

Are you wondering how identical twins might differ so much from one another in such a small way?

Let's look at the intriguing science that underlies it.

Twin Types: Not All Twins Are Created Equal

To understand why fingerprints differ, we must first look at the two main types of twins—identical and fraternal—and how they form.

Twins That Don’t Look Alike, or Non-Identical Twins

Fraternal twins are produced when two different sperm fertilize two different eggs. Since they share about half of their DNA, they are genetically identical to any other sibling. But, what are fraternal twins? They are also known as dizygotic twins. They come from two separate eggs, fertilized by two different sperm. They also share about 50% of their genetic material, and have unique physical traits, often different sexes at birth too.

Because of this genetic variability, fraternal twins, like non-twin siblings, can have different sexes or distinct hair and eye colors.

Twins That Are Identical

Identical twins, on the other hand, develop from a single fertilized egg that divides into two embryos. Their DNA is almost the same, but not exactly the same, thanks to this process. Also known as the monozygotic twins come from a single fertilized eggs that splits into two embryos. These twin share the same genetic material, which is what leads to their identical physical traits and the same sex at birth. However, there are slight differences that can emerge due to environmental factors during pregnancy, including the space in the womb.

According to a 2021 study referenced by Smithsonian Magazine, only 38 pairs of identical twins and two sets of triplets had completely identical genes. Because of their tight genetic ties, they have remarkable physical similarities, such as similar skin tones, eye colors, and hair colors. However, minor distinctions like height, weight, and fingerprints distinguish them.

Fingerprints: Not Just Genetic Information

Although fingerprint patterns are influenced by heredity, environmental variables within the womb provide a twist.

Experts in forensic science say there is almost little likelihood that identical twins' fingerprints will match. Although they may have similar overall characteristics, such ridges and loops, the specifics are different.

The following factors affect fingerprints:

• Access to nutrition during pregnancy
• The length of the umbilical cord influences blood flow.
• Growth rates of fingers
• Placement inside the womb
• Both DNA and these environmental influences shape fingerprints, which are fixed for life by the 13th to 19th week of foetal development.

Solving the Fingerprint Mysteries

According to some research, twins' fingerprints could seem similar at first glance, but a deeper look reveals variations in the pattern branches and ridge spacing.

According to the National Forensic Science Technology Centre, no two individuals—not even identical twins—have ever been found to have the same fingerprints.

It adds even more individuality because even your own fingers have different prints!

Even as the Indian Meteorological Department (IMD) continues to predict rising temperatures and heatwaves in most parts of India, especially in Delhi, doctors flag a quiet but terrible effect that can alter the demographics of the country.

Heatwave conditions are likely to persist in Delhi-NCR from April 23 to 25, with maximum temperatures expected to climb by 1-2°C and remain above normal for at least five days, according to the latest weather bulletin by the India Meteorological Department. The mercury has already been hovering between 40°C and 42°C.

Some parts of the national capital on Friday recorded the season’s first heat wave, even as the India Meteorological Department issued a yellow alert, warning that similar conditions may continue on Saturday.

Beyond Delhi, heatwave conditions are likely to continue over the plains of northwest and central India, including parts of Punjab, Haryana, Rajasthan, Madhya Pradesh, and Uttar Pradesh.

India is already seeing a drop in fertility rates, reaching the replacement level of 2.0 as per the National Family Health Survey

-5 (2019-21) and continuing to decline to 1.9 by 2023 in the Sample Registration System report.

But with rising heat, both male and female reproductive health could be at risk.

Emerging research suggests that extreme heat can disrupt hormonal balance, reduce fertility in both men and women, and even affect pregnancy outcomes. From lowering sperm quality to interfering with ovulation, scorching temperatures may have deeper biological consequences than many realize.

Heatwave And Women’s Reproductive Health

Dr Archana Dhawan Bajaj, a gynaecologist and IVF expert at Nurture IVF Clinic, noted that heat stress can directly affect hormonal balance.

“During extreme heat conditions, we see women coming in with complaints of irregular menstrual cycles, delayed periods, and worsening symptoms of conditions like PCOS."

"The body’s hormonal system is extremely sensitive to environmental stress, and prolonged heat exposure can disrupt normal functioning in ways that are often overlooked,” she said.

Working in extreme heat can double the risk of stillbirth and miscarriage for pregnant women, according to 2024 research from India published in the BJOG: An International Journal of Obstetrics and Gynaecology.

A 2025 study led by researchers from the Arizona State University in the US showed that thermal stress reduces sperm quality and increases miscarriage risk.

Heat stress could disproportionately impact vulnerable populations, especially in low-income countries. Heat and air pollution could synergistically worsen reproductive health outcomes.

Heatwave: The Impact On IVF Outcomes

Dr. Hrishikesh Pai, Consultant Gynaecologist & IVF Specialist, Lilavati Hospital, Mumbai, highlighted that the rising temperatures are not only hurting natural pregnancy but also affecting outcomes of fertility treatments like IVF.

"We are seeing extreme heat during the summer months for the last couple of years. This is making pregnancy more challenging for some women due to poor egg quality and implantation difficulties," he said.

Dr Pai noted that as a result, women with reduced chances of natural conception are moving to "assisted reproductive techniques like IVF, but environmental and lifestyle factors are increasingly playing a role in treatment outcomes."

Heatwave: Impact on Sperm

Further, men’s health is also being impacted, particularly when it comes to fertility.

A 2024 study by Argentine researchers, published in the journal Science of the Total Environment, showed that semen from men exposed to heat waves had lower sperm number and abnormal morphology.

The differences were 4–5 times higher in peak heatwave years (2013, 2023). Heat wave length was negatively associated with semen quality.

“Rising temperatures are a serious but often overlooked risk factor for male infertility. The testicles need a cooler environment compared to the body to function properly in producing sperm. Any slight increase can affect their numbers and quality," said Dr Vineet Malhotra, Head of Urology and Director, VNA Hospital.

"When exposed to hot temperatures over an extended period of time, especially in urban areas, there is an increase in low-quality sperm, genetic mutations, and infertility in men,” he added.

How To Prevent?

The experts urged both men and women planning pregnancy to

• Avoid prolonged periods in the heat.
• Take regular shade breaks if working outdoors on hot days.
• Avoid exercising or sunbathing for long periods in the hottest part of the day.
• Wearing light clothing,
• Maintain proper hydration.

Even as the Indian Meteorological Department (IMD) issued a yellow alert for heatwave and rising temperature in Delhi, the state government issued guidelines for all schools, focusing on hydration and safety measures.

The IMD has forecast heatwave conditions at isolated places in Delhi from today, with maximum temperatures expected to climb between 41 °C and 44 °C through April 24.

Also Read: US CDC Study Showcasing COVID Vaccine Benefits Blocked From Publication

The guidelines issued by the Directorate of Education (National Capital Territory of Delhi) are applied to all government-aided and private unaided recognized schools. The guidelines call for:

Outdoor Assemblies: Outdoor assemblies are to be curtailed or conducted in shaded/indoor areas with minimal duration. No open-air classes are to be conducted.

Water Bell Initiative: Schools shall implement a "Water Bell" system, whereby a bell is rung at regular intervals (every 45-60 minutes), reminding students to drink water to prevent dehydration.

Display of IEC Material: IEC (Information, Education and Communication) material issued by the Health Department, Government of NCT of Delhi, on heat wave precautions shall be prominently displayed at visible locations in schools, including notice boards, corridors, and classrooms.

Awareness Sessions: Schools shall conduct short awareness sessions/briefings for students during class hours/assembly to educate them about preventive measures, the importance of hydration, and the identification of symptoms of heat-related illnesses. Immediate first aid and medical attention must be ensured wherever required.

Buddy System: Establishing a buddy system wherein each student may be paired up with another student during school hours to monitor and take care of each other's physical well-being.

Outdoor Activities: It must be ensured that students avoid outdoor physical activities.

Regular Advisory Updates: Class teachers shall share advisories of the India Meteorological Department (IMD) with parents through their respective class-specific WhatsApp groups, ensuring regular guidance and awareness regarding heat safety measures. Schools shall share daily heat wave forecasts and alerts with students through prayer time/assembly and notice boards to ensure timely awareness and necessary precautions.

Appropriate Clothing and Personal Hygiene: Parents are advised to ensure that their wards come to school dressed in light, breathable cotton clothing. They should also reinforce the importance of personal hygiene, including daily bathing, to help children stay fresh and reduce the impact of heat.

The DoE also directed each school to designate nodal officers who will be responsible for the implementation of monitoring the water bell initiative, awareness sessions, and display of IEC materials.

Heat-Related Illnesses: Symptoms And First Aid Measures

The DoE noted that the symptoms of heat-related illnesses include:

• Nausea and increased sweating
• Vomiting
• Acts or talks confused
• Muscle cramps
• Fainting,
• Weakness,
• Dizziness
• Body temperature rises to 40.5°C (105°F) or higher

First aid measures to follow if you feel dizzy or uneasy

• Drink water to rehydrate
• Move to a cooler place immediately
• Loosen clothes if possible
• Sponge with water
• If unconscious, do not force-feed or give water
• If symptoms persist, immediately visit the nearest health centre or call an ambulance.

Heatwave In India: Which States Are On Alert?

Beyond Delhi, a heatwave alert has been issued for:

• East Uttar Pradesh from April 21 to 25.
• Madhya Pradesh, Chhattisgarh, and West Uttar Pradesh from April 22 to 25,
• Odisha and Rajasthan between April 23 and 25.
• Gangetic West Bengal and Bihar for April 21 and 22,
• Vidarbha from April 24 to 26.

Digital devices have become the new pacifiers, said Zerodha co-founder Nithin Kamath, raising concerns about the growing impact of excessive screen time on children's behavior and brain development.

Posting a video of cognitive neuroscientist Jared Cooney Horvath on his social media platforms, Kamath warned that while digital devices often help parents manage their schedules, they can also create long-term dependency among children.

"For most parents, digital devices have become a pacifier; it's a way to keep 'em quiet, and it's understandable, but it ends up creating a dependency in the long run," Kamath said.

In the video, Horvath spoke about a decline in learning abilities among younger generations due to the increasing screen time. Horvath said children today appear to lag behind previous generations in areas such as attention span, memory, literacy, numeracy, and executive function, despite spending more time in formal education.

Kamath noted that his son studies at a school where digital devices are not permitted, and screen use at home is restricted to 30 minutes a day. Despite these limits, the billionaire entrepreneur pointed out how quickly children become drawn to short-form digital content.

"At Kiaan's (son's) school, no digital device is allowed, and at home, we restrict screen time to 30 minutes a day. But even then, it is crazy, the addiction to reels/clips; I normally catch him browsing through that," the billionaire entrepreneur said.

Horvath said children today appear to lag behind previous generations in areas such as attention span, memory, literacy, numeracy, and executive function, despite spending more time in formal education.

Long Screen Exposure Can Impact Vision, Brain Development

Dr Sriram Simakurthy, Chief Medical Officer, Sankara Eye Hospital, Hyderabad, flagged the risk of excessive screen exposure in children with eye health.

“Children can develop particular vulnerabilities because they spend extended periods using screens without taking breaks, and they struggle to identify their symptoms before they become serious. Children who spend extended time looking at screens will face an increased risk of developing myopia (near-sightedness),” the expert said.

Prolonged screen exposure causes people to blink less frequently, which leads to unstable tear film production that results in dry eyes and eye irritation.

Dr. Sreenath S Manikanti, Clinical Director & Senior Consultant - Neonatology and Pediatrics, Rainbow Children’s Hospital, said that kids' eye health gets harmed by excessive screen exposure through mechanisms that extend beyond digital eye strain.

Also read: Can 'Eye Strain' Lead To Brain Cancer? Experts Explain

“The extended periods of near-focus work, which include watching screens for too long, create a permanent requirement on the eye to focus, which leads to visual fatigue and alters normal eye development in children. The period of visual system development happens throughout children's growing years,” the expert said.

Dr. B K Madhusudhan, Lead Consultant – Neurology, Aster RV Hospital, Bengaluru, noted the impact of screen time on brain development.

“The brain development process in children gets disrupted when they spend too much time using screens because that time replaces their necessary developmental activities. The continuous use of screens results in decreased attention spans, which makes it difficult for children to maintain focus during extended periods and to complete tasks that require their full attention,” Dr Madhusudhan said.

When screen time replaces parent-child conversations, storytelling, and peer interactions, this change impacts language and communication development. These experiences help children develop vocabulary skills and reasoning abilities as well as social understanding.

“Some children also develop impulsive behavior patterns and struggle with emotional control and information processing because they spend excessive time using screens,” Dr. Madhusudhan said.

How To Prevent?

The experts advised people to balance their screen use with outdoor time.

• Take breaks following the 20-20-20 rule
• Keep a proper viewing distance
• Schedule eye examinations for children at regular intervals.