The term ‘double-standard’ has been used since at least the 18th century to refer to the inequitable treatment of women.
The philosopher and activist Thomas Paine wrote this in the Pennsylvania Magazine in August 1775
:
[Women] are constrained in the disposal of their goods, robbed of their freedom of will by the laws and victimised by a pernicious system of double standards.
It was in 1930s USA that the expression ‘double standard’, referring to the sexual promiscuity applauded in men and and decried in women began to be commonly used. For example, this piece from the Californian newspaper The Fresno Morning Republican, January 1930:
Why marry? We have shifted from the old-fashioned double standard, where girls had to be pure, white, unkissed lilies and men visited the tawdry districts on a Saturday night. But we have not shifted to a regulation fair and square single standard.
That assessment, that the double standard had been done with in the 1930 seems wildly over ambitious, as it is clearly still going strong today.
‘Double standards’ apply in any branch of law, business or social relations where one group has more power than another. The old proverb ‘there’s one law for the rich and another law for the poor‘ is an early expressions of such double standards.
Other ‘double’ phrases:
Double cross
Double, double toil and trouble, fire burn, and cauldron bubble
Double Dutch
Double entendre
Double whammy