Bras do nothing to help support a woman's breasts and could even be doing damage, research has found.
For years, women have been taught the virtues of a good bra in order to make the most of their assets and defy the pull of gravity.
Now a French study has claimed that breasts gain no benefit from underwear support and that women would in fact do better to go without.
Prof Jean-Denis Rouillon, of Besancon University, spent 15 years studying the anatomy of 330 women before concluding that bras are a "false necessity".
Using a slide rule and a calliper, he found a 0.27in (7mm) difference in the height of busts, with those who went without the support of a bra faring best against gravity.
The research found that breasts were firmer and sagged less in the women studied who did not wear a bra and that women were no more likely than others to suffer from back pain.
"Medically, physiologically, anatomically – breasts gain no benefit from being denied gravity," he said.
Prof Rouillon, a sports scientist, who has been researching the subject since 1997, suggested that breasts become "dependent" on lingerie support once women start wearing it, meaning that supporting muscle is underused and degrades more quickly.
He said his initial results validated the hypothesis that the bra is a false necessity but that he would not advise women who have relied on bras for years to cast them aside.
Some of the women who took part in the experiment, at the Centre Hospitalier Universitaire in Besancon, said that stopping wearing a bra had eased back pain.
• Underwired bras could kill keen walkers, the Mountaineering Council of Scotland has said. The wire in bras, plus magnets in mobile phone cases, GPS devices and car keys can affect compass needles and may lead to potentially fatal navigational errors, it warned. (© Daily Telegraph, London)