The Supreme Court decision in Adkins v. Children's Hospital, 1923.

But the ancient inequality of the sexes, otherwise than physical, as suggested in the Muller Case has continued "with diminishing intensity." In view of the great - not to say revolutionary - changes which have taken place since that utterance, in the contractual, political, and civil status of women, culminating in the Nineteenth Amendment, it is not unreasonable to say that this inequality has now come almost, if not quite, to the vanishing point. In this aspect of the matter, while the physical differences must be recognized in appropriate cases, and legislation fixing hours or conditions of work may properly take them into account, we cannot accept the doctrine that women of mature age, sui Juris, require or may be subjected to restrictions upon their liberty of contract which could not lawfully be imposed in the case of men under similar circumstances. To do so would be to ignore all the implications to be drawn from the present day trend of legislation, as well as that of common thought and usage, by which woman is accorded emancipation from the old doctrine that she must be given special protection or be subjected to special restraint in her contractual and civil relationships.