The differences between men and women run deep. Very deep. Right down to the level of what goes on inside the billions of cells that make our bodies tick.
But the world of medical science, which you'd think would be on top of this, has been somewhat slow to recognise it.
For decades, most health research has been based largely on human studies of men only, or of male lab animals.
It wasn't done to deliberately shut out women and their differences.
Rather, it was a misguided attempt to get around the fact women and female lab animals had hormonal cycles that were thought to complicate results. (They don't, as it turns out).
The trouble is that excluding females from research has meant important sex differences have been missed or misunderstood, with potentially serious consequences for women's health.
But women aren't the only ones getting the rough end of the pineapple.
In a handful of cases — like osteoporosis, depression, and male breast cancer — the opposite is true; scientists have used data primarily from women to draw conclusions about men.
Of course it's not just your biological sex that shapes your health. Your gender, the social and life experiences you have because of your sex, plays a massive role too. And gender isn't binary, it exists on a spectrum. But it's undeniable that biology matters.
While there's a push to change this situation in the research world now, it will take decades for the body of knowledge to catch up.
Meanwhile certain aspects of health and disease definitely show themselves differently in men compared to women.
Here are five examples.
1. Men can tolerate more pain
It's often said childbirth has meant women are better built to withstand pain.
But experts say there's now overwhelming evidence that women are more sensitive to pain and have a lower tolerance to pain than men.
This doesn't mean any individual woman will feel pain more than any individual man — there's a big overlap between the sexes.
But overall, it seems men can be exposed to a greater pain stimulus than women before they feel pain or reach the point where they can't take it any more.
At least this is what controlled experiments in the lab have shown for a variety of pain types. Real life pain is more difficult to study because it's hard to measure and control.
Women's greater pain sensitivity may be part of the reason they experience more chronic pain conditions than men. In fact, 70 per cent of chronic pain patients in the world are women.
The most common type of chronic pain is headache and it affects 50 per cent more women than men. (No jokes about 'not tonight I have a headache' please).
Many factors likely play a role in how men and women respond to pain — different genes and sex hormones for a start.
There's even some evidence completely different cells might be involved in processing pain signals in males versus females, which might feasibly affect how well different painkillers work.
But how we experience pain and the extent to which we express our pain to others is also shaped by our social relationships and gender. For instance, women may talk about pain more openly, while men might downplay serious pain.
2. Women have more active immune systems
Anyone who can prove conclusively whether men really do get sicker with 'man flu' — or just act sicker — should send their findings to the Nobel Prize judging committee ASAP.
In the meantime, scientists agree that in general, women have more active immune systems than men — producing a bigger and more responsive army of cells and chemicals to do battle with invading pathogens like bacteria and viruses.
It seems the hormone oestrogen has a role in this robust response, while the male hormone testosterone seems to dampen things down.
This could be part of the reason why women are less prone to many infections, including sepsis and many parasitic and fungal infections, compared to men.
It's also known that men are 1.5 times more likely to die from the bacterial lung disease tuberculosis, for example.
But having a super-charged defence system has its down side: women's immune systems are more likely to overreact.
This can cause women's immune systems to attack healthy tissues, leading to disorders like rheumatoid arthritis, lupus and multiple sclerosis.
There are more than 70 of these so-called autoimmune diseases, most of which affect women far more than men. In fact, almost 80 per cent of people with autoimmune diseases are women.
Women are also more responsive to many vaccines, including the flu vaccine.
This may be why they are more likely to have minor adverse vaccine reactions, including a headache or a sore red area on their arm after a vaccination.
3. Heart attacks can be different in women
Many people still don't know that coronary heart disease —the build-up of fatty deposits in blood vessels supplying the heart — is the biggest killer of women in Australia.
It's the chief cause of heart attacks — when the supply of blood to the heart muscle is blocked.
However, a heart attack in a woman can look quite different from a man's. (And Hollywood movies often don't do a great job of depicting either).
In both men and women, chest pain or tightness that radiates to the left shoulder and arm is the most common sign of a heart attack.
But in women, there's a greater chance there's no chest pain or tightness at all.
Women are more likely than men to instead have shortness of breath and pain in the back of the neck or jaw, along with more general symptoms like nausea.
These 'atypical' symptoms may be perceived as gradual, mild and intermittent rather than sudden and dramatic — one reason women may be slower to seek medical help.
Even when they make it to hospital, women are twice as likely to die from their heart attack.
There's differences at a micro level too, with abnormalities in the lining of smaller blood vessels having a greater role in heart events in women compared to men.
Since angiograms — where dye is injected to look for blockages — look only at the large arteries supplying the heart, women whose small blood vessels are affected can sometimes be told their heart is fine. Yet they might still have a heart attack if the condition isn't treated.
One heart condition, stress cardiomyopathy (also known as Takotsubo cardiomyopathy) — where the main pumping chamber of the heart fails and balloons with blood — affects almost exclusively women.
It can imitate the classic symptoms of heart attacks and is usually linked with physical or emotional stress.
4. The male gut is the fast lane
Real men don't eat quiche, the adage goes.
But a man who sensibly ignores such rules will likely find the delicious savoury tart passes through their digestive tract more quickly than if it is eaten by a woman.
In general, women have less muscular activity in the gut, which means food takes longer to complete its journey through the body.
This is thought to be why women are more prone to constipation.
It may also partly explain why bloating tends to be less of a problem for men compared to women.
Bloating is around eight times more common in women.
On average, both men and women produce around 25 litres of gas in their gut every day.
Women tend to retain more of this gas in the small and large intestine, which can lead to an uncomfortable 'full' feeling.
There may be a flip side to this disparity.
It seems men and women also differ in how often they fart.
Farting is perfectly normal and certainly never life-threatening (although those around you may at times feel otherwise). On average, we all release around 1.5 litres of gas a day.
But the higher level of muscular contractions in the male gut might explain why men 'let off' more than women — 12 times a day on average, versus seven for women (yes, someone actually studied this).
Bear in mind though, there is a large range and it's not known what role different eating patterns and social inhibitions influence this.
The hormone oestrogen also leaves women much more likely to develop gallstones.
The make-up of digestive juices is different in men versus women too. The enzyme that breaks down alcohol, for instance, is five times more active in men.
This means women get drunk more quickly and the alcohol hangs around for longer in their bodies.
Anyone for baked beans and a beer?
5. Our bodies can respond differently to medications
There are a myriad of reasons why men and women may respond differently to medications.
Differences in everything from organ size, body weight, fat distribution, and blood flow patterns to the amounts of enzymes that break drugs down in the liver can be involved.
These factors can affect how a drug is absorbed into the body, how quickly it works, how it is broken down and how long it lasts.
It's known for instance that the kidneys tend to clear certain medications out of a woman's system at a slower rate than a man's. So certain drugs may require a lower dose in women.
Examples include digoxin (trade name Lanoxin and others) used to treat heart failure and gabapentin (Neurontin and others) and pregabalin (Lyrica and others) used to treat nerve pain.
Women are also known to be more sensitive to opioid pain relievers, the antidepressants known as SSRIs (selective serotonin reuptake inhibitors), antipsychotics (given for psychiatric disorders like schizophrenia) and beta blockers (given to slow the heart rate).
Women are also up to 70 per cent more likely to experience unexpected or unpleasant side effects (adverse events) from medicines than men.
One of the most striking examples of sex differences in medication response is with the sleeping drug zolpidem (trade names in Australia include Stilnox and Zolpibel, and in the US, Ambien).
A study found more women than men had problems with mental alertness and driving the day after taking zolpidem, even if they didn't feel drowsy.
It turned out women had much higher blood levels of the drug the next day because their bodies were slower to clear it.
This information came to light only after products containing zolpidem had been on the market for nearly 20 years.
In 2013, the US Food and Drug Administration revised their dosage advice, recommending that women take only half the dose of zolpidem recommended for men.
But in Australia, dosage advice for zolpidem remains unchanged. A review by the relevant authority here, the Therapeutic Goods Administration, concluded there wasn't enough evidence to warrant it.
Note: While there is no evidence of serious safety issues from men and women taking the same doses of most medications, more research is needed. If you feel a medication is not working well or needs a dose adjustment, discuss your concerns with your doctor before making any changes. You can also report and get professional advice on medicine side effects via the Adverse Medicine Events Line 1300 134 237.