I don't.

But with the exception of new parents and six-year-olds, most of us don't talk about it.

But could our number twos be the answer to some of the world's biggest problems?

The average adult flushes away 730 liters of pee and around 91kg of feces every year.

But are we missing a trick?

In Ancient Rome, no human waste went to waste.

Untreated excrement was used as manure in kitchen gardens, while urine was used to produce fabric.

In Henry VIII's time, one of the country's top positions was Groom of the Stool.

Wiping the king's bottom was well worth it for the benefit of having his ear.

"About that castle..."

Cesspits were emptied overnight by gong farmers who sold the content to local farmers.

Urine was collected and used to soften leather.

While it's probably sensible to leave untreated manure in the past where it belongs—think of the pathogens—we can learn from our predecessors' attitude to poo.

It could be the solution to some of our most pressing problems of today.

Let's start with our need for energy.

Unlike solar or wind power, which can be unreliable, all it takes is a healthy fiber intake to ensure a constant supply of poo.

Now that's a whole other kind of wind power.

The sludge left behind after sewage is processed is good raw material for generating methane.

Modern treatment plants add bacteria to the sludge, generating bio-gas, which can be piped to homes or used to power vehicles.

It's a much cleaner fuel than petrol or diesel.

While poo has plenty of uses, there's a reason wee is number one.

Seventy two percent of global water use is in agriculture, and population increases coupled with climate change will only exacerbate the demand for water.

Some countries could face having populations displaced by water scarcity within the decade.

In addition to the two liters of pee each adult in the UK produces daily, each adult also sends around 140 liters of water used at home down the drain.

Could recycling that water save the planet from apocalyptic droughts?

Absolutely.

The technology is available and already in use.

Israel currently captures almost 90% of used water which is recycled to provide a whopping 56,000 Olympic swimming pools' worth of water annually for agricultural use.

Speaking of agriculture, every living thing relies on phosphorous to survive.

But due to chronic overmining, it's a rapidly declining natural resource which can't be replenished.

The US, China and India might run out of their domestic supplies in the next generation.

Without adding this vital nutrient to farmland, humanity could only produce around half the food it does today.

We could however emulate our ancestors and return our sewage to the soil, making use of solutions such as composting toilets, or the nutrient-rich dried residue left over from bio-gas generation.

Reinventing the toilet could also be a gamechanger for 4.2 billion people currently living without access to safe sanitation.

Innovative toilet designs that operate without water could help prevent the deaths of an estimated 800 children under five each day.

Bill Gates predicts this developing toilet market would not only be lifesaving but lucrative.

By 2030, toilets could become a six billion US dollar market, with every dollar spent providing a $5 return.

While poo remains a word that never fails to raise a giggle, your fecal matter is no laughing matter.

If we act now, poo may very well help to save the planet.