Despite our differences in opinion and cultures, there’s one thing just about everyone can agree on: Sex is amazing. No matter how much we may enjoy it, though, it’s one of the most mysterious aspects of evolution. Scientists have been trying to answer why we have sex at all for quite some time now,^[1] as from an evolutionary perspective, it doesn’t quite make sense.

Not only is sexual reproduction quite costly for the organisms, evolutionarily speaking, but we also don’t quite know for sure why we find so many things, like breasts, for example, sexually arousing, especially when other animals that also reproduce sexually aren’t like this.

Now, we’re not saying that we’re closer to figuring out the evolutionary reasons for sexual reproduction than qualified scientists, but we can certainly look into the various theories that try to do just that. Even if none of these definitively answer the question, they provide some interesting insights into this awesome yet mysterious feature of humanity.

10 Sex Could Have Helped Speed Up Evolution

A big reason why scientists are consistently scratching their heads over sex is that we don’t know for sure that it provides any benefits over asexual reproduction in evolutionary terms. Asexual reproduction is simple: You take an organism, divide it in two, and produce an offspring that is identical to the parent. There’s no risk for introducing new genetic disorders to your genetic line, and you don’t have to make the effort of finding a mate to reproduce.

According to one theory, the cost of sexual over asexual reproduction could well be offset by a boost in the speed of adaptation to new environments for sexual creatures. A study done on a type of single-celled green algae that reproduces sexually backs it up, too.^[2] If not for sexual reproduction, the theory suggests, life would have taken a lot longer to develop the adaptation mechanics needed to adapt to new environments, so that’s another thing we have sex to thank for.

9 Sex May Have Evolved As A Response To Parasites

Humanity may have won the evolutionary war now, but that victory was a long time coming. It was a brutally competitive world out there, with many organisms fighting for the same resources in the same area. It wasn’t just huge predators, either; many life-forms were just as threatened by parasites. According to some scientists, sexual reproduction had a huge role to play in resisting them.

It’s known as the Red Queen Hypothesis, one of the various theories that try to explain why we reproduce sexually despite all its disadvantages. It suggests that as parasites tend to attack, and adapt to attacking, genetically similar organisms (like in the case of asexual reproduction), sexual reproduction would have helped keep offspring genetically unique and hence at a lower risk of a parasitic infection.

Researchers even carried out an experiment on a freshwater snail found in New Zealand which can reproduce sexually as well as asexually. They found that the part of the population that reproduced asexually had a much higher chance of being infected by a worm parasite than the others, suggesting that sexual reproduction evolved as a natural response to parasites.^[3]

8 The Female Orgasm Could Be A By-Product Of Orgasms In Men

There’s no bigger mystery regarding sex than the female orgasm. Many men have trouble getting their female partners to it, and scientists cannot wrap their heads around why it exists at all. Unlike the male orgasm, the female orgasm doesn’t do anything for reproduction, as women have a whole different mechanism for producing eggs that’s not reliant on male performance in the bed. So, what gives?

According to one theory, the female orgasm serves absolutely no evolutionary purpose and is actually a by-product of orgasm in males developed early during gestation, when the fertilized egg goes through the same stages of development regardless of whether or not it ends up male.^[4] There are plenty of other theories to explain the female orgasm, though this one stands out because we know of another feature that serves no purpose and only exists as a by-product of development in the other sex: male nipples.

7 Humans Aren’t Meant To Be Monogamous

Cheating in a relationship has probably existed for as long as relationships themselves. No matter how committed most couples are to each other, cases of one of them going out and sleeping with someone else are abundant, so much so that memes about it are a subculture of their own on social media. It’s less of an evolutionary mystery and more a social anomaly; we’ve been doing one-on-one relationships throughout our history, so we should have gotten used to them by now.

According to science, though, there’s a simple reason behind why we have such a hard time staying in long-term, committed relationships. It’s because we never evolved to be monogamous in the first place and were always meant to have multiple sexual partners. This isn’t to say that we should forsake monogamy, as a lot of our accomplishments have come from going against how we we’re designed, but remaining faithful to our partners definitely doesn’t come to us naturally.^[5]

6 Oral Sex Could Help Avoid Miscarriages

Oral sex is a rather important part of foreplay in any sexual encounter, unless we’re talking about people who are just bad in bed. Many would argue that it’s not just a prelude to the final act but an intrinsic part of the act itself. All the same, if we look at oral sex from an evolutionary perspective, it doesn’t make sense. We don’t know why it causes arousal or why, in many cases, it can serve as a passable alternative to intercourse, which is what’s actually needed for reproduction.

According to studies, oral sex, at least when performed on men by women, may have developed as a way to have fewer miscarriages. One study found a definite link between swallowing sperm and a reduced risk of preeclampsia in women, a condition which certainly increases the risk of miscarriage.

A Dutch team of obstetricians looked into it further and found more links between oral sex and a lower risk of miscarriages. They think that it’s because when the female gut is exposed to male semen, the body is able to develop immunity toward antigens present in it.^[6]

5 Foot Fetish May Safeguard Against STDs

Even if a lot of us may outright deny that it exists in public, foot fetish is perhaps one of the most common types of fetishes around. It’s more common than you’d think, and despite its obvious appeal for those who find feet attractive, science simply has no idea why it exists, evolutionarily speaking. The feet are easily the last thing someone trying to find a partner would flaunt, which rules out any reproductive merit it may have had in the past. Freud suggested that some people find feet sexually attractive because they kind of look like the penis, which is verifiably not true if you ask anyone who has both.

According to a more plausible theory, our fetish for feet may have developed as a response to widespread STDs. In a study, researchers looked at all the times the foot was sexualized in popular imagination in history.^[7] They were surprised to find that all those times coincided with whenever there was an STD outbreak in that region, though the study was largely limited to Europe. In a way, it makes sense, as the feet may have emerged as a safer alternative to regular sex when it got too risky.

4 Women Have Permanently Enlarged Breasts Due To Bipedalism

The opinion on breasts worldwide is simple: Just about everyone loves them. They’re an important organ for arousal for both men and women during sex. It almost sounds like blasphemy to question their existence, but for the sake of knowledge and science, we have to: Why do breasts exist at all?

If you’d say all animals have them, that’s not really true. Take apes: The only time their breasts are enlarged is when they’re lactating, and as soon as that’s over, they go back to flat chests. Human females are the only ones who have permanently enlarged breasts, and science has been trying to figure out why for quite some time, with little success.

According to some scientists, though, the breasts developed as a natural response to humans standing up on their own two feet during evolution. You see, when we were on all fours, the breasts provided no attraction benefits for the females, and it was the back end that served as the most visible part of the female reproductive anatomy. When we stood up on our feet, we developed breasts as another way of attracting better mates for reproduction.^[8]

3 Homosexuality May Have Survived Due To Society’s Opposition To It

Homosexuality is another mystery scientists have been trying to crack for some time now, as it flies against all the theories of evolution and sexual reproduction we currently have. We know that it’s genetic to an extent, and we know that gay people exist, even if they’re a minority of the general population. There has got to be some way that it’s being successfully passed down to subsequent generations. This is despite the obvious fact that homosexual sex cannot naturally yield children.

Well, according to one evolutionary biologist, society’s ostracizing of gay people throughout history may have had a big role to play in homosexuality surviving through the ages.^[9] As it was less okay to come out in the earlier days, gay people were forced to enter straight marriages, which led them to having babies and helping the population to survive. And the statistics back it up; 37 percent of the LGBT community in the US has children, and around 60 percent of them are biological.

2 Female Moaning May Be A Call To Other Men In The Vicinity

Moaning during sex is a perfectly natural response, though you may have noticed that women tend to do so much more than men. Some may say that it’s because men don’t tend to show emotions unless it’s absolutely necessary, but even for men who do make sounds during sex, they’re generally nothing compared to the ladies. Moaning may seem like a response to sexual pleasure during the act, though evidence suggests that it has nothing to do with orgasm, as the sounds actually subside when women are close to climax.

According to some theories, it may be more of a social response than a sexual one. Studies suggest that there’s a specific reason why women moan so loudly during sex: It’s because they’re inviting other men to the party in case their current partner is unable to fertilize their eggs. They tested this hypothesis on baboons and found that the males listening to a couple having sex could learn a lot from the nature of the sound, like how likely the female is to be impregnated by the ongoing act.^[10]

It may not apply to modern, mostly monogamous society, though it would have greatly helped our chances back when promiscuity encouraged the survival of the species.

1 Sex May Not Be About Reproduction At All

In the evolutionary biology circles, sex is considered to be one of the biggest anomalies, as we’ve mentioned above. If we go by the popular notion that it’s the best way for us to reproduce, it comes across as hugely disadvantageous for the species. If we didn’t have two sexes and just reproduced on our own, we could grow our species twice as fast. There’s also the question of males, as due to reproducing sexually, we also have to bear the cost of a gender that does comparatively next to nothing for reproduction (strictly evolutionarily speaking, of course).

According to one theory, we may just be looking at it the wrong way. Sex may not have anything to do with reproduction at all. Rather, it developed as a way to exchange and collect useful genes in the earliest stages of evolution. (We still don’t have a definitive idea on exactly when life started reproducing sexually.) The theory is called the libertine bubble theory, which argues that sexual reproduction originated at a time when we were nothing but “bubbles” in the primordial soup, with genetic information all over the place. These “bubbles” developed sex as a way to attach useful DNA information to each other to get the best of everything that was out there, and it just stuck over time.^[11]

You can check out Himanshu’s stuff at Cracked and Screen Rant, get in touch with him for writing gigs, or just say hello to him on Twitter.

Let’s face it: the internet sure loves a good conspiracy theory. Truthers, Birthers, lunatics who believe Sandy Hook is a government plot . . . wherever you look, someone is peddling some outrageous claim that most of us would dismiss as nonsense. But what about the handful of theories that are harder to dismiss? The ones backed up by strangely plausible facts and figures? I’m talking weird-ass stuff like:

Robert Falcon Scott’s race to the South Pole was one of exploration’s biggest screw-ups. Not only did his team fail to claim the Pole for the British; they were pinned down by a ten-day blizzard on the way back and froze to death. Crappy luck doesn’t come much crappier than that.

Unless, that is, there was no blizzard. In 2001, science writer Susan Solomon caused a stir by claiming the ten-day storm was impossible. See, Antarctic weather follows some pretty neat patterns: when cold air builds up above the continent, it creates a sort of ‘reservoir’ that overflows, causing storms. When this ‘reservoir’ is empty, the storms let up. In decades of measurements this has never taken ten days.

Even more damning, any super-storm that hit Scott should have by rights continued on to the coast. Except another team was taking measurements down there and recorded no indications of a storm raging inland. So what happened? According to the theory, Scott was so upset about losing the race that he and his teammates committed suicide, filling their diaries with stories of an impossible storm to hide the dismal truth.

In 1999, a series of explosions shook Russia. Gigantic bombs planted by Chechen terrorists leveled entire apartment blocks and killed nearly three hundred people. In the aftermath, Russia launched the Second Chechen War, and the rest is history.

Except for the part where the FSB (the sequel to the KGB) deliberately bombed its own people. Now, theories like this emerge in the aftermath of any tragedy, but for once there’s actually some evidence to back it up. Firstly, the terrorists denied any involvement in the attacks—an unusual response given that they’re, you know, terrorists.

Secondly, high-ranking ex-FSB defector Alexander Litvinenko claimed it was all a cover-up. That’s the same defector poisoned in 2006 with polonium-210, a death so unlikely under any other circumstance they might as well have carved ‘The Kremlin woz ere’ into his chest. Add to that the suspicious assassination of a journalist who investigated the claim, and it’s easy to see why this particular theory is still around.

In 1988 Pan-Am flight 103 detonated in the skies over Scotland, killing everyone on board and raining deadly-wreckage down on the village of Lockerbie. Thirteen years later, low-level Libyan intelligence officer Abdel Baset al-Megrahi was convicted of the bombing and imprisoned. And there the case would have ended, were it not for the enormous pile of evidence indicating that the attack was really carried out by Iran.

In 1988, Iran was still reeling from a tragedy of its own: five months earlier the US Navy had shot down a civilian plane carrying 290 Iranian citizens, killing them all. In the immediate aftermath, the Ayatollah vowed retaliation, promising ‘the skies will rain with blood’. So the motive was there—as well as the means.

Weeks before the blast, a group of Palestinian terrorists was arrested with four devices identical to the Lockerbie bomb. Intelligence reports indicated that the group had strong Iran links, and that a fifth device was ‘missing’. Then there’s Libya’s lack of motive, coupled with the unlikelihood of a single intelligence officer being able to carry out such a complex attack under his own steam. So why didn’t we pin this on Iran decades ago? The short answer is: no-one knows.

Harold Wilson was twice-elected Prime Minister of Great Britain and a mild social reformer. According to some sources, he was also an undercover KGB agent tasked with . . . well, no one’s actually sure. Giving people something to talk about before Thatcher came along?

What’s interesting about this theory is that almost everyone believed it—and this certainly had some bizarre consequences. When a high-ranking Soviet defector claimed the Prime Minister was a Russian stooge, MI5 immediately opened a file on him. By the time 1974 rolled around, the military was so sure he was a traitor that they came within months of staging a coup d’état backed by the freakin’ Royal Family. According to the BBC and the Guardian, army brass planned to seize Heathrow, the BBC and Buckingham Palace and force the Queen to read a speech asking people to support the new military junta.

Bear in mind that this is Britain, not some banana republic—and these guys were honestly considering the pros and cons of going full General Franco. And all to remove a Prime Minister who resigned for health reasons a few weeks later anyway.

Nixon is probably the most unpopular president in history. Aside from once nearly putting a hit out on a journalist , he was also at the epicenter of one of the few scandals in history where the conspiracy theorists were probably right. And I’m not talking about Watergate.

The 1968 Presidential campaign was fought on a knife-edge. The Vietnam War had become an abattoir for America’s youth and everyone wanted the damn thing over and done with. So when the two sides came to the negotiating table in the dying days of LB Johnson’s presidency, it looked like a great boost for the Democrats. Then, on the eve of the election, the South Vietnamese pulled out the talks. Bummer, eh? Well, not quite: according to a cache of recently-released tapes, Johnson was certain Nixon was involved. As in, he’d deliberately sabotaged the peace process and then lied about it to give himself an electoral advantage.

If this were true (and there’s a ton of evidence supporting it), that would mean Nixon committed treason, sentenced hundreds of thousands of kids (both American and Vietnamese) to violent death, and wrecked the lives of millions more—all so he could be king of the castle. Could even Nixon be that flagrantly psychopathic? What do you think?

In 1983, a group of armed men burst into the Ballymany Stud in Co Kildare, Ireland and kidnapped the prizewinning racehorse Shergar. After loading him into a trailer, they drove off into the morning mist and the horse was never seen again. So what happened?

Well, there are a number of theories, but only one likely one: that the IRA killed him in a botched ransom attempt. While nothing’s been proved, there’s quite a bit of testimony. IRA informer Sean O’Callaghan claimed Shergar was kidnapped to raise money for arms, while a Sunday Telegraph investigation in 2008 reported that the Army Council had the horse machine gunned and buried when they realized he was worthless. However, insurance companies have never paid out against the horse’s death, and to this day his disappearance officially remains a mystery.

During the Cold War, Russia and the Allies weren’t exactly BFFs. For fifty years, both sides tried to hide their failures from each other, creating a climate where you couldn’t be sure what was real and what was propaganda. So when a Czech agent leaked information about a failed Russian spaceflight in December 1959, no one knew what to make of it. According to the story, Yuri Gagarin’s successful 1961 trip into orbit was only one in a long line of Soviet space attempts—and merely the first one that didn’t end in the pilot’s gruesome death.

Worryingly, there may even be some evidence to this. In February 1961—two months before Yuri’s flight—a listening station in Italy apparently recorded two Russian voices broadcasting the words “everything is satisfactory, we are orbiting the Earth” from space. A few days later, they picked up another garbled transmission that sounded a whole lot like a scream of terror, followed by empty silence.

Two later recordings were also made, including one of three sobbing people saying “Conditions growing worse, why don’t you answer? . . . We are going slower. . . the world will never know about us. . .” So what were they? Clever fakes? Evidence that Russia abandoned irrecoverable cosmonauts to a horrifying fate? We may never know.

In 2010, an inmate at a maximum-security Israeli jail hanged himself, triggering a flash flood of accusations, revelations, and bizarre conspiracy theories. Articles linking ‘Prisoner X’ to Mossad, Hezbollah, and Australian Intelligence surfaced, alongside accusations of Israeli foul play. At the time of writing, all we really know is that he was an Australian/Israeli called Ben Zygier and probably had links to intelligence operations. But that didn’t stop Der Spiegel advancing a theory so lurid it may just be true.

This conspiracy theory has it that Zygier was a former Mossad field agent who had been demoted to a desk job. Bored with his new life, Zygier set up a rogue operation to crack Hezbollah and win over his superiors. So far, so John le Carre. But what allegedly happened next is full-blown Hollywood. An agent Zygier recruited from Hezbollah turned double agent, reporting back to Lebanese Intelligence. This in turn led to the arrest of several high-level Israeli spies in Arab nations, and a rush to find the mole at Mossad. All told, Zygier was allegedly responsible for the biggest information leak in Mossad’s history; leading to a prison sentence so harsh he saw only one way out. Could such a pulpy story possibly be true? You decide.

The CIA doesn’t exactly have the most level-headed history, so when talking about CIA conspiracy theories, you have to bear in mind there are literally hundreds of them. And some, like Operation Midnight Climax, are so well-documented they’re no longer really theories, so much as ‘the truth’. So it’s nice to know that even in our jaded modern era, they’re still capable of shocking stuff.

In the mid-90s, a three part newspaper series called ‘Dark Alliance’ briefly made shockwaves throughout the media. Basically, reporter Gary Webb more-or-less accused the CIA of having connections with Nicaraguan drug dealers operating in the United States. In the resulting furore, Webb was smeared in the media, and his claims that the CIA was deliberately getting African Americans hooked on drugs dragged through the mud. Only, Webb wasn’t claiming that at all. All he was doing was saying that the CIA was working with some pretty bad dudes down south—including guys who were running drugs on American soil—and that he had the proof. So what happened? The media hounded him to suicide, and everyone completely forgot about his earth-shattering story.

Did he, didn’t he? It’s one of the biggest conspiracy questions that will ever be asked: did FDR know Pearl Harbour was about to be attacked? Basically, it would be impossible to cram all the proofs, counter-proofs, and general crack-pottery into a single article entry, so I’m not even gonna try. But there’s a good deal of (non-conclusive) evidence that the British-sympathetic FDR may have known the Japanese were on the verge of launching an attack, and allowed it to happen—triggering America’s entry into WWII.

Think about it: if this is true, his decision changed the course of history. Without American firepower, the Western front would have reached a stalemate at best—leaving the Russians to slap down Hitler single-handed. Without an advancing Allied army to keep them in check, the Soviets could have run riot across Europe, placing millions more people under Stalin’s control. There would have been no A-Bomb, no operation Paper Clip giving the US an edge in the space race . . . in short, the world as we know it would be completely unrecognizable. Now there’s a scary thought.