Published Mar 30, 2026 | 7:00 AM ⚊ Updated Mar 30, 2026 | 7:00 AM
Sperm deposited during intercourse can survive two to three days inside the female reproductive tract.
Synopsis: Sperm carry almost no cytoplasm. The thin outer layer in most cells holds the repair machinery and the antioxidants. Sperm stripped of it have no tools to fix themselves when damage accumulates. They burn through stored energy. They generate oxidative stress. Their DNA, wound tight around proteins called protamines, begins to fracture.
Every morning, inside a man’s body, millions of sperm queue in the dark. They wait in coiled tubes and ducts, packed tight, burning through whatever fuel they arrived with. Nobody sends them more. Nobody fixes the ones that break.
They just wait.
For decades, fertility clinics around have been telling men to abstain from sex or masturbation for two to seven days before producing a sample. The logic seemed to hold: rest longer, collect more sperm, improve the odds. The World Health Organisation has put the guidance in writing.
A study published this month in the Proceedings of the Royal Society B questions that logic. Researchers at the University of Oxford, after sifting through 115 human studies covering 54,889 men and 56 studies across 30 other species, found something that goes against the old advice: the longer sperm wait, the worse they get.
Picture a long-distance runner told to stay on the starting line for a week. By the time the gun fires, his legs have seized.
Sperm, the Oxford team explained, carry almost no cytoplasm. The thin outer layer in most cells holds the repair machinery and the antioxidants. Sperm stripped of it have no tools to fix themselves when damage accumulates. They burn through stored energy. They generate oxidative stress. Their DNA, wound tight around proteins called protamines, begins to fracture.
The meta-analysis found that men who abstained longer showed measurable increases in sperm DNA damage and oxidative stress. Sperm motility, the ability to swim toward an egg, declined. So did sperm viability.
“Even if you collect an ejaculate every hour from a person, each sample will still contain sperm,” Dr Krishna Chaitanya Mantravadi, Scientific Head and Clinical Embryologist at Oasis Fertility, Hyderabad, told South First. “There is a common misconception that sperm only builds up over three, five, or seven days. That is not how the body works.”
What he described matched what the Oxford researchers called the post-meiotic sperm senescence. Sperm age on their own clock, ticking from the moment they finish forming, independent of the man’s age entirely.
The testes, Dr Mantravadi explained, contain millions of microscopic tubules, almost like coiled strands, each with multiple segments where production runs without pause. “From a single germ cell, four sperm cells are formed, and this process is ongoing every minute. All of this production gets stored in a collection area, and whenever ejaculation occurs, it is released.”
The problem, both the Oxford study and Dr Mantravadi point to, is not production. It is what happens to sperm that never leave.
Here is where a widespread misreading of the science has quietly shaped how couples approach fertility, inside clinics and outside them.
“The WHO guideline is often misunderstood,” Dr Mantravadi said. “It is not meant as a routine lifestyle recommendation but as a diagnostic tool.”
The logic behind asking a man to abstain for two to seven days before a semen analysis is deliberate. The abstinence period allows sperm to accumulate and exposes them to oxidative stress. If, after that period, count and motility remain normal, it tells the clinician that the body’s defence mechanisms function well. The test is a stress test, not a template for daily life.
But somewhere between the clinic and the couple, the instruction migrated. Men who follow the seven-day guideline as a general fertility strategy, saving up for the fertile window, may be doing the opposite of what their bodies need.
“Longer abstinence can have downsides,” Dr Mantravadi said. “Sperm DNA, which carries the father’s 23 chromosomes, can undergo fragmentation as abstinence increases. In many cases, men may have normal sperm count and motility, yet face difficulty conceiving because of underlying DNA damage.”
This matters because standard semen analysis does not catch DNA fragmentation. A man can walk out of a clinic with a reassuring report and still carry damage that works against conception.
Co-lead author Dr Rebecca Dean from Oxford’s Department of Biology put it this way: “Sperm are highly mobile and have minimal cytoplasm. They quickly exhaust their stored energy reserves and have limited capacity for repair.”
After ovulation, a human egg survives for roughly 12 to 18 hours. That window does not negotiate.
“Studies suggest that 40 to 50 percent of couples miss this fertile window, often because they are not sexually active frequently enough,” Dr Mantravadi said.
The Oxford data supported the prescription he has been giving his patients. Sperm deposited during intercourse can survive two to three days inside the female reproductive tract. If a couple has sex on Monday, Wednesday, Friday, and Sunday, sperm remain present in the fallopian tubes continuously. When ovulation arrives, something is already there to meet it.
“The challenge, especially in urban life, is that this regularity is often missing,” Dr Mantravadi said.
He described couples who arrive at his clinic and pause when asked when they last had intercourse. Some couples limit sex to predicted fertile hours flagged by ovulation-tracking apps, removing spontaneity and, in some cases, removing the frequency that makes conception more likely in the first place.
“Intercourse should not become a highly scheduled or mechanical activity,” he said. “Just like eating when you are hungry or sleeping when you are tired, sexual activity is a natural, regular biological function during reproductive age.”
The Oxford study reaches into evolutionary biology to ask a question that sounds unusual until the answer lands: why do male animals, including humans, masturbate at all?
One hypothesis the researchers raised: ejaculating may function as a form of biological maintenance. Sperm stack in order of production, with older cells sitting nearest the exit. The first ejaculate carries the oldest, most damaged batch. The second carries fresher cells. Regular ejaculation cycles the population, discarding deteriorating sperm before they drag down overall quality.
Lead author Dr Krish Sanghvi framed it this way: ejaculates should be understood as populations of individual sperm that undergo birth, death, ageing, and selective mortality.
A population under turnover. Not a static reservoir.
Dr Mantravadi arrived at the same conclusion through clinical observation. “Regular ejaculation is important. In cases where ejaculation happens only once in seven to ten days, or even less frequently, the issue is not production, but the ageing and quality of sperm when it is not released regularly.”
There is a harder conversation sitting underneath this research, one that clinicians in India navigate more carefully than the science alone demands.
“Even today, despite progress since the 1980s when infertility was largely seen as a female issue, there is still a perception among men that if they can have normal intercourse, nothing can be wrong,” Dr Mantravadi said. “That is not true.”
Male factor infertility contributes to roughly half of all cases where conception does not occur. Yet men remain, in Dr Mantravadi’s experience, the harder group to reach.
“Women are generally far more receptive and compliant when it comes to fertility care. With men, it is often more difficult. You tell them to lose weight or stop smoking, and many will agree in the moment, but not act on it. I still see patients stepping out of clinics and smoking, citing stress.”
Many fertility centres now employ counsellors specifically to navigate this resistance, because direct correction often does not land with male patients the way it does with female ones.
The Oxford findings added a biological dimension to what is already a behavioural challenge. Lifestyle factors, including smoking, alcohol consumption, obesity and lack of exercise, generate the oxidative stress that damages sperm DNA. That damage does not show on a standard semen report. A man can score well on every metric that a basic test measures and still carry the kind of damage that the Oxford meta-analysis identified as the primary mechanism of sperm deterioration during storage.
At a fertility clinic, a couple walks in carrying hope and anxiety in equal measure. The man has followed the instructions: abstained for five days, produced his sample, and handed it over. He did what he was told.
The Oxford data and Dr Mantravadi’s clinical experience suggested that in some cases, he may have waited too long.
For procedures like intracytoplasmic sperm injection, where a single sperm is selected under a microscope and injected directly into an egg, quality matters more than quantity. In those cases, the researchers argued, shorter abstinence periods, closer to 48 hours, produce better results. Other recent evidence points in the same direction: men who ejaculated within 48 hours of providing a sample showed improvements in embryo development during IVF.
The upper limit of seven days in the WHO guidelines, the Oxford team concluded, may be too long. The overall effect in men, while statistically significant, remained modest, so the recommendation comes with caution. Not every man waiting five days will produce worse sperm than the man who waited two. But the direction is consistent.
For Dr Mantravadi, the clinical implications run further than sample collection timing.
“If a couple has been trying to conceive for one year with regular intercourse and no contraception, and pregnancy has not occurred, they should seek medical advice. Delaying this is a major issue in India. Many couples spend years relying on rituals or other non-medical approaches, and by the time they come to a doctor, valuable time has been lost.”
In species other than humans, the Oxford team found a pattern running across 30 species: females preserve sperm better than males do. Female reproductive tracts in many species contain specialised organs that release antioxidants and nourishing fluids around stored sperm, acting as a maintenance crew.
Senior author Dr Irem Sepil described these as potential templates for laboratory sperm storage technology. Evolution, in other words, worked this problem out long before reproductive medicine did.
The same principle, applied to male biology, points toward one conclusion. The body is not designed to wait. Sperm age in the dark, burning through fuel they cannot replace. Regular ejaculation, whether through sex or masturbation, keeps the population turning over.
“I often tell my patients,” Dr Mantravadi said, “if you can spend long periods on your phone or watching content, it is difficult to argue that you cannot make time for intimacy. It is not about complexity. It is about consistency.”
A study covering 54,889 men and 30 species, conducted across three continents, arrived at exactly the same conclusion.
(Edited by Majnu Babu).
