Young women with a well paid job in the developed world will be almost 40 percent poorer than their male colleagues by the time they reach old age.

That's according to study by Swiss bank UBS.

It shows on average, a 25 year old woman living in a rich country earns 10 percent less than a man of the same age.

By the time they turn 85, the gender pay gap will result in the woman having 38 percent less wealth the man.

That gap will widen if the woman takes a gap year or decides to work part- time for a period of her life.

The study says, as women are expected to live longer, it's harder for them to maintain their lifestyle in retirement, having to stretch their wealth over a longer period.