Generations of men have brushed with conjugal disaster over whether to leave the toilet seat up or down.

It’s been a cause of abiding disharmony as recalcitrant partners refuse to budge on whether to put the interests of themselves or their female partner first when finishing up in the bathroom.

Science has, so far, declined to inquire into such conflict-ridden territory, leaving it to the citizen truth-seekers who prop up hotel bars and inhabit bubbly infused social events.

However, science has now gone where no man or woman has gone before seeking truth in the toilet about that other contentious question: should you flush with the lid up or down?

The accepted wisdom has been that to stop germs and other nasties from spraying out of the bowl and into the air, it’s more hygienic to put the lid down before flushing.

University of Arizona researchers studied two types of toilet – one in a public facility and the other in a residential home. The public toilet was tankless, contained within a stall and flushed with a pressurised water line. The home toilet had a tank and was situated in a small room.

Viral particles were added to the toilets, which were then flushed. One minute later, the boffins measured contamination on the toilet itself and nearby surfaces.

They found there's little difference whether you leave the lid up or down. Closing the lid on a toilet does not prevent the spread of viral particles from a flushed toilet. Lid down or not, microscopic viral particles spread to the floor and nearby restroom surfaces.

The only meaningful way to reduce the spread of viral pathogens such as norovirus is to disinfect the toilet, toilet water and nearby surfaces, the study found.

If you want a clean bathroom after flushing, then a bit more elbow grease is needed in disinfecting all surrounding surfaces.

“You really have to make sure you always clean the toilet seat and other areas in the restroom,” microbiologist and research lead, Charles Gerba, said.

Nevertheless, the advice is to keep the toilet area sanitary. This can be done by keeping a disinfectant spray near the toilet as well as disinfectant wipes to clean the toilet handle after use. Also, thoroughly wash your hands and use hand sanitiser, especially if someone in the household is infected with a virus.

These measures may be less likely in a public toilet, depending on your own level of commitment (and your carry room for disinfectant and wipes).