IT is one of the greatest female dilemmas and has led generations of women to ask: "Does my bum look big in this?"
Now, a team of researchers from Edinburgh's Heriot-Watt University are launching what is believed to be the world's first scientific study to answer the often asked question of how clothing can affect the appearance of the female rear.
The team, from the university's School of Textiles and Design, based in Galashiels, believe the study could have major implications for retailers.
Female volunteers wearing hundreds of different types of clothing will have their behinds photographed for the research.
Participants will then be asked to look at the pictures to assess how big or small each model's backside appears. The study will examine how various designs, colours, patterns and fabric types affect perception of bottom size.
Dr Lisa Macintyre, who is leading the research, said four models had been chosen to provide as representative as possible a sample of female rears. One has a "standard" womanly backside while another has a much fuller "pre-Raphaelite" bum, like television presenter Liza Tarbuck's.
The academic said the third model was slim with a small bum while another had a curvier behind like actress and singer Jennifer Lopez.
Dr Macintyre, 33, from Edinburgh, said: "There's much discussion in the media of clothing styles that flatter the body and it's generally accepted that enhancing body perception can improve confidence and self-esteem.
"But the factors behind this have never been fully investigated in a proper scientific manner."
She added: "Designers and consumers don't currently have access to established information that could enable them to make or choose garments that enhance body size and shape.
"This study will provide for the first time detailed and usable information that would enable designers to make the clothes that help women make the most of their natural assets." The results from the first phase of the study, which will look at how different styles of trouser affect the appearance of bottom size, are to be published in May.
Dr Macintyre, whose PhD was in dressings for burn scars, plans to apply for a government research grant to expand the study.
It is the latest off-the-wall piece of research to come out of the Capital university, often with far-reaching results.
Yesterday it emerged that scientists from Heriot Watt had developed powerful anti-MRSA antibiotics on the surface of a particular brand of kitchen sponge scourer in one of a string of revolutionary inventions to be created at the university this year.
The scourers, which are sold in packs of eight for 89p at Morrison's supermarket, are the only surface the bacteria, first found growing on long-stranded fucus seaweed in the Firth of Forth, will grow on.
Just last week, research from Heriot-Watt pioneered a new type of 3D digital printing which could revolutionise the way traditionally hand-painted toys, such as model trains, are made.
And earlier in the year, the university's researchers developed a revolutionary weapon in the fight to improve Scotland's appalling record on tooth decay. A dental insert, which is biodegradable over time, slowly releases anti-caries agents to strengthen teeth and reduce the number of bacteria causing tooth decay.