Born in Paris, as Desirée Véret, she worked as a seamstress before in 1831 joining the followers of utopian socialist Henri de Saint-Simon.
The following year, with Marie Reine Guindorff, she founded the Tribune des femmes, edited by Suzanne Voilquin, in reaction to the exclusion of women from decision making among the Saint-Simonites.
[3] In 1840, the Gays tried to found a school in Châtillon-sous-Bagneux which aimed to educate children from birth, but this failed, probably due to lack of capital.
[3] While the two were able to obtain 12,000 francs from the National Assembly to form an association of women seamstresses making ladies' underwear,[8] Gay chose not to take part in establishing the organisation.
This ceased in mid-1891, and this may mark her death; a visit by Considerant to Brussels in November did not lead to a meeting with her, and may have represented his attendance at her funeral.