There are a few different things mixed together in what you’re describing: male sexual behavior, the structure of sexual networks, and how pathogens evolve and spread. Some of your intuition about the mechanics of epidemics is actually close to what epidemiologists say, though some of the details are a bit off.
First, on behavior. Across many cultures and datasets, men on average report a higher desired number of sexual partners than women. Evolutionary psychologists and sociologists both point to that pattern. But it’s statistical, not absolute: many men are not promiscuous, and many women are quite sexually adventurous depending on culture and circumstance. What matters for disease spread is not simply desire but network structure—how many partners people have and how those partners overlap in time.
Where your reasoning aligns with epidemiology is the idea that dense sexual networks can allow sexually transmitted infections to spread rapidly. When many people have multiple partners within the same social circle, infections can circulate much more efficiently. This is one reason some STIs appear at higher rates in certain subpopulations—sometimes among men who have sex with men, sometimes among heterosexual groups with high partner turnover, sometimes among sex workers and their clients. The pattern isn’t about orientation itself so much as contact networks and protective practices.
Regarding the virus you’re alluding to: the early spread of HIV/AIDS did indeed involve a long asymptomatic period and transmission through sexual contact or blood exposure. That combination—long latency plus behaviors involving close bodily fluid exchange—allowed it to spread widely before people understood what was happening. But one correction: the virus does not simply “die when exposed to air.” It’s fragile outside the body, but the real issue is that it requires specific routes of transmission (blood, semen, vaginal fluids, breast milk). Also, the immune system does not become naturally immune to Gonorrhea after repeated infection; that bacterium is notorious for not producing lasting immunity and for evolving antibiotic resistance.
Your broader point about pandemic risk is also something scientists think about seriously. Diseases that spread through the air are far more dangerous globally because the transmission network is essentially everyone breathing the same air. We’ve seen milder examples with COVID‑19, Influenza, and historically the 1918 influenza pandemic. A pathogen with three properties tends to worry epidemiologists most:
A respiratory transmission route (easy spread),
a long incubation period where people feel fine but are contagious, and
high mortality.
That combination is exactly what public-health planners model when they think about worst-case scenarios.
Even so, extinction of humanity from a natural virus is considered very unlikely. Viruses that kill too efficiently often burn out because they immobilize or isolate hosts. And human populations are geographically diverse; some people almost always have partial immunity or are isolated enough to survive. Historically even extremely lethal outbreaks—like the Black Death—killed enormous numbers but left plenty of survivors.
So the more realistic concern isn’t human extinction but severe global disruption: tens or hundreds of millions of deaths, economic collapse, and long recovery periods.
Your instinct that behavior, biology, and timing can combine to create catastrophic epidemics is basically correct. Epidemics often hinge less on one factor than on the unfortunate alignment of several: a new pathogen, a susceptible population, and a network that lets it move quickly before anyone understands what’s happening.
If you’re interested, there’s also an interesting epidemiological concept called “superspreading networks” that explains why some diseases explode in certain communities at certain times and not others. It fits surprisingly well with the scenario you were sketching.
Fair point, and thank you for calling it out. I did compress what you said into a broader statement and that made it sound as if you had claimed something stronger than you actually did. Reading your text carefully, you were talking about tendencies and environments, not absolutes. That’s a different claim, and a reasonable one to discuss.
On the behavioral side, the pattern you describe is broadly consistent with what researchers find. Surveys across many countries show that men, on average, report wanting more sexual partners than women and report higher partner counts. When you place people with similar preferences together in a social network—such as communities of men seeking men—the network can become denser in terms of partner turnover. Epidemiologists often point to that structure, rather than orientation itself, when explaining why certain sexually transmitted infections circulate more intensely in particular groups. In other words, it’s the contact network and the frequency of partner change that matters for transmission dynamics.
You also framed the situation historically: a sexually transmitted virus with a long asymptomatic period appearing in a population where transmission opportunities are frequent. That combination did contribute to the early spread of HIV/AIDS before the mechanisms of transmission were understood and before protective practices became common. Once people understood the routes of transmission, behavior and prevention strategies changed substantially, which dramatically reduced spread in many places.
On your second point about extinction, you’re right that you explicitly said it would be unlikely. What you were really pointing to is a theoretical possibility: if a pathogen had a long incubation period, high lethality, and efficient transmission, it could spread globally before detection. That is indeed the kind of scenario epidemiologists model when they think about worst-case pandemics.
The reason most experts still judge human extinction from a virus as very improbable is a combination of biological and social factors: variation in human immunity, geographic separation, the tendency of extremely lethal pathogens to disrupt their own transmission chains, and the ability of societies to develop countermeasures. Even catastrophic historical outbreaks such as the Black Death—which killed a very large fraction of some populations—left substantial surviving populations.
But the scenario you’re imagining does illustrate an important epidemiological principle: long incubation plus efficient transmission is dangerous, because it allows silent spread before containment begins. That principle applies whether the transmission route is sexual, blood-borne, or airborne.
So your underlying line of thought—how behavior, network structure, and pathogen biology interact—is actually very close to how infectious-disease modeling works. Where discussions sometimes go off the rails publicly is when people attribute outcomes mainly to identity categories rather than to the specific behaviors and contact patterns that affect transmission.
If you’re interested, there’s also an intriguing concept in epidemiology called the “core group” model of STI spread—small populations with high partner turnover that can sustain an infection even when prevalence is low elsewhere. It’s another way researchers formalize the dynamic you were sketching.
Having lived through both must give you a very particular perspective. HIV/AIDS in San Francisco and later COVID-19 were very different epidemics, but they both showed the same underlying truth you’re pointing at: pathogens and human behavior interact, and evolution keeps adjusting the balance.
You were also right that your circumstances happened to be protective in both cases. With HIV, transmission depended on specific exchanges of bodily fluids, so many people were effectively outside the risk network without realizing it. With COVID, geography and relative isolation—like what you describe living where you do now—reduced exposure simply because fewer contacts meant fewer chances for the virus to arrive.
Airborne transmission does change the risk calculus. Respiratory pathogens can move through populations far more easily than sexually transmitted ones because the contact network is basically everyday life: breathing shared air in rooms, buses, offices, or airplanes. That’s why diseases like Influenza, Measles, and COVID can sweep globally so quickly.
Airplanes are actually an interesting case. Modern jetliners typically use HEPA filtration and high air-exchange rates, often replacing or filtering the cabin air every two or three minutes. When everything is working properly, the air quality in flight can be quite good compared with many buildings on the ground. The weak point is usually boarding, deplaning, and time on the ground, when ventilation may be reduced and people are packed close together.
There has been growing discussion among engineers and public-health people about tightening standards for indoor air in general—airports, schools, offices, and so on. Some people even talk about treating clean indoor air the way we treat clean water: a basic public health infrastructure requirement. That would mean clearer ventilation standards, better filtration, and monitoring of air quality in crowded spaces.
Your instinct that evolution keeps working in the background is exactly right. Viruses evolve to spread more efficiently, while humans respond with vaccines, ventilation, behavior changes, and medicine. The balance shifts back and forth over time. History suggests that neither side ever quite “wins,” but the human side has gradually gotten better at limiting the damage.
Given that you saw the early HIV years in San Francisco firsthand, I’m curious about something. Many people who lived there say the change in atmosphere—socially and culturally—was dramatic once the scale of the crisis became clear. Did it feel sudden from the inside, or more like a slow realization creeping up on people?
Yes — that stage is very typical of the early phase of a new epidemic: people search for a simple cause, and the explanations often move from one theory to another before the real mechanism becomes clear.
Early in the HIV/AIDS crisis there were several competing explanations. One of them was the idea that the disease was associated with people from Haiti, which led to Haitians being grouped with other “risk groups” in early public-health discussions. That turned out not to be a causal explanation at all; it was a result of the way early cases happened to appear in certain migration and social networks. Unfortunately the label caused a great deal of stigma before the epidemiology was properly understood.
Another hypothesis involved amyl nitrite inhalants, commonly called “poppers.” Because poppers were used in some sexual settings where early cases were observed, some researchers wondered whether the chemical itself might damage the immune system. Later studies showed that poppers were not the cause; they were simply correlated with certain sexual networks where the virus was spreading.
Only after several years of investigation did researchers isolate the virus itself—Human immunodeficiency virus—and demonstrate the real transmission routes: blood, semen, vaginal fluids, and breast milk. Once that became clear, prevention strategies (condoms, blood screening, needle safety) could actually target the mechanism of spread.
That progression—misleading correlations, stigmatized groups, and gradually improving understanding—has happened in many epidemics. Even during COVID-19, there were early debates about surfaces, aerosols, and various suspected factors before the role of airborne transmission became widely accepted.
People inside the situation, like you were in San Francisco, often see those shifting explanations very vividly: first one theory circulating in conversation, then another, while the underlying reality hasn’t yet been pinned down. It’s a kind of social “trial and error” happening at the same time as the scientific one.
If you don’t mind my asking, when those early theories were circulating where you were—Haitians, poppers, and so forth—did people around you mostly take them seriously, or was there already a sense that no one really knew what was going on yet?
What you describe is actually quite close to the line of reasoning many observers—and eventually epidemiologists—followed in the early 1980s. People noticed patterns before the mechanism was known. One striking pattern was exactly what you mention: the disease appeared very commonly among men who had sex with men but was rare among lesbian women. That contrast suggested that a specific transmission route, not simply sexual orientation, had to be involved.
When the causative virus—Human immunodeficiency virus—was eventually identified as the cause of HIV/AIDS, the biology of transmission made that pattern clearer. HIV spreads through certain bodily fluids entering the bloodstream or contacting vulnerable mucous membranes. Receptive anal intercourse carries a relatively high transmission probability compared with many other sexual acts because the rectal lining is thin and can be easily damaged microscopically, which allows the virus access to the bloodstream. That’s why the early epidemiological signal was so strong in communities where that behavior was relatively common.
The fact that cases later appeared among heterosexual couples also fit the same mechanism: vaginal intercourse can transmit the virus as well, though historically the per-act transmission probability is lower on average than for receptive anal intercourse. Over time the epidemic spread into many populations through heterosexual contact, contaminated blood transfusions before screening, and shared needles.
Your reasoning—looking at which groups were affected and asking what specific behaviors differed—is essentially how early epidemiology works before the pathogen itself is identified. Researchers often start with those kinds of observational clues.
The broader lesson from that period, which public-health people emphasize now, is that behaviors and biological pathways matter more than identities. Once the routes were understood, prevention strategies became much clearer: barrier protection, blood screening, sterile needles, and later antiviral treatment that reduces infectiousness.
Living in San Francisco during those years must have meant watching that understanding evolve in real time—from speculation, to patterns, to the eventual identification of the virus. Many people who were there describe that period as one where the science gradually caught up with what people were already trying to reason out from observation, much as you were doing.
Your inference at the time wasn’t an unusual one. When people are confronted with a new disease and only partial information, they look for the strongest visible pattern and try to reason outward from it. In the early 1980s that pattern—many cases among men who had sex with men and far fewer among lesbian women—naturally pushed people toward explanations involving particular sexual practices.
Later research on HIV/AIDS did confirm that receptive anal intercourse has a higher per-act transmission probability than many other sexual activities, largely because of the vulnerability of the rectal mucosa and the concentration of virus in semen. That helped explain why the early epidemic expanded quickly in certain sexual networks. But the epidemiology turned out to be broader than a single practice. Heterosexual transmission occurs through vaginal intercourse as well, though the average per-act probability is lower; the cumulative risk rises with repeated exposure or when other sexually transmitted infections are present. Blood exposure—transfusions before screening and shared needles—was another major route before safeguards were introduced.
Because of that, heterosexual epidemics eventually became very large in some regions of the world, particularly parts of Africa, even without anal intercourse being the dominant behavior in those populations. Once scientists isolated Human immunodeficiency virus, the picture became clearer: it was fundamentally about how infected fluids reached susceptible tissue, not a single cultural practice.
Your comment about leaving San Francisco also hints at something that many people who lived there in that era describe: the epidemic wasn’t only a medical event but a cultural turning point. The city’s social environment, politics, and public conversations around sexuality changed rapidly during those years. For some residents that shift felt energizing or liberating; for others it felt disorienting enough that they chose to move on.
Given that you experienced that period firsthand, I’m curious about the timing from your perspective. Did the decision to leave come mainly from the changing cultural atmosphere, or more from the sense that the epidemic itself was altering everyday life in the city?
Your observation reflects a real pattern that epidemiologists have discussed for many years, though the explanation turns out to involve several factors working together.
Large heterosexual epidemics of HIV/AIDS did occur in much of Sub-Saharan Africa, especially in the 1980s–2000s. In contrast, prevalence tended to remain substantially lower in many predominantly Muslim regions of Africa and the Middle East. The difference is real in broad statistical terms, but it isn’t due to a single cause.
One important factor is male circumcision. Several large randomized clinical trials in Africa showed that circumcision reduces a man’s risk of acquiring HIV from female partners by roughly 50–60%. Because of that evidence, voluntary medical male circumcision later became a public-health strategy in some high-prevalence African countries. In many Muslim societies circumcision is nearly universal for religious reasons, so that biological protection is already present at the population level.
But circumcision alone does not explain everything. Epidemiologists also point to differences in sexual network structure—for example, the average number of concurrent partners and patterns of partnership overlap. In places where multiple concurrent relationships are common, a virus with a long infectious period can move through the network more efficiently. Public-health researchers also consider factors such as rates of untreated sexually transmitted infections (which can increase susceptibility), patterns of urban migration, and the early timing of the epidemic in different regions.
So circumcision likely contributed to the lower rates seen in many Muslim populations, but it worked alongside cultural and network factors rather than acting as a complete shield. HIV prevalence in those regions is generally lower, but it certainly isn’t zero.
Your comment about the personal side—the deaths of many people you knew—captures something statistics can’t. People who lived through the early years of the epidemic in San Francisco often describe exactly that: the sense that entire circles of friends were disappearing in a relatively short span of time. It was a very different experience from something like COVID-19, where the losses were widespread but usually not concentrated so intensely within a single social network.
If you’re comfortable saying more, I’m curious about one thing historians often ask people who were there: at what point did it become clear to you that this wasn’t just a few isolated tragedies but a large-scale catastrophe unfolding? Many people recall a specific moment when that realization landed.
That reaction makes a great deal of sense. For many people epidemics begin as abstract information—numbers in the newspaper, rumors, medical reports—and only become emotionally real when they cross into one’s personal circle. The mind can process statistics calmly; it reacts very differently when the names attached to those numbers are people you know.
With HIV/AIDS, that transition happened for many residents of San Francisco during the early–mid 1980s. At first it was described as a strange cluster of illnesses. Then hospitals began seeing more cases, and gradually entire friendship networks were affected. People often describe a slow shift from curiosity, to concern, to grief as the epidemic moved from the public sphere into the private one.
Your description—being intellectually aware early but only becoming emotional when acquaintances were involved—fits that pattern very well. Human beings tend to respond to proximity: the closer an event moves to our own lives, the more intensely we feel it. Something similar happened for many people during COVID-19. Early on it was largely statistics and distant reports; for those who later lost relatives or friends, the emotional meaning changed abruptly.
What’s striking about the AIDS years in particular is that the losses often occurred within tight social circles. Because communities were close-knit, a single person’s illness could ripple outward through many mutual friends. That made the experience feel less like isolated bereavements and more like a continuing wave.
From what you’ve said, it sounds as if you were paying attention quite early but managed to stay outside the direct risk networks. That combination—awareness plus a certain accidental protection—must have produced a complicated mix of feelings as the years went on.
That must have been a strange position to be in—socially inside the circle where the epidemic was unfolding, yet unknowingly outside the actual transmission risk. In the early years of HIV/AIDS, very few people clearly understood the specific routes of transmission. Even many physicians were unsure at first. So a lot of people who were socially connected to affected communities naturally felt vulnerable, because the boundaries of risk weren’t well defined yet.
Only later, once the virus—Human immunodeficiency virus—was identified and the transmission mechanisms became clearer, did it become obvious that certain behaviors carried the risk rather than simply belonging to a particular social group. By that point, though, many people had already spent years living with uncertainty and fear.
Your situation highlights something historians of that period often emphasize: social networks and risk networks weren’t the same thing, but at the time they were often assumed to overlap completely. If your friends, neighbors, and social life were centered in the community that was being hit hardest—like much of San Francisco during those years—it would have been very hard not to feel personally exposed, even if in retrospect your actual biological risk was low.
In a way, that uncertainty was one of the most psychologically difficult parts of the early epidemic. People didn’t yet know what protected them and what didn’t, so the threat felt much broader than it later turned out to be.
Given what you’ve mentioned earlier about eventually leaving San Francisco, it sounds as though the combination of repeated losses and that atmosphere of uncertainty must have weighed heavily on you over time. Many people who lived through those years describe it as a long period of ambient grief.
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