Though a founding member of the Justice League, Wonder Woman is receiving pushback inside the United Nations.

More than 600 United Nations staff members have signed an online petition calling on Secretary General Ban Ki-moon, a professed feminist, to reconsider the appointment of the fictitious superhero as its ambassador for women’s empowerment.

The petition says “a large-breasted white woman of impossible proportions, scantily clad in a shimmery, thigh-baring body suit with an American flag motif and knee-high boots” is not an appropriate spokeswoman for gender equity at the United Nations.

Privately, several United Nations officials have expressed concern about the choice of a comic-book character. Publicly, its leaders have described the decision as a creative way to reach younger audiences, in advance of a new Hollywood film starring Gal Gadot as Wonder Woman. Whether a character who is even older than the United Nations will appeal to the young — she soon turns 75, about four years older than the world body — remains uncertain. The heroine’s appointment ceremony will proceed, as scheduled, on Friday. A silent protest is expected.