The first known representation of the curled-up god, in
the Twenty-first Dynasty papyrus, illustrates the earth's fertility by showing
the god engaged in oral self-impregnation. His curled-up position may have
provide the artist's inspiration for this unique iconography. The papyrus
explicitly identifies the god as 'Geb, the father of the gods, the great god
who made the earth and all that the sun encircles'. None of the four later
parallels corroborates the god's name. A feature characteristic of the
Graeco-Roman representations is the androgynous nature of the figure which has
replaced the sexual act depicted in the mythological papyrus as an indication
of the god's fertility. At Deit el-Haggar the figure displays female hairstyle
and breast, but the sexual organ is male (cf. fig. 3). Both the Philae and
Dendara reliefs represent the figure with a female breast but without other
distinctive female traits. As for male traits, the Dendara figure wears a
beard, but no sexual organ is indicated. (Olaf E. Kaper, "The Astronomical Ceiling of Deir
El-Hagger in the Dakhleh Oasis," The Journal of Egyptian Archaeology
81 [1995]: 180)
The distinction is to be made between androgynous figures
and purely male figures shown with pendulous breasts, as was noted by J.
Baines, Fecundity Figures (Warminster and Chicago, 1985), 118-21. The
breasts on the curled-up god are female. (Ibid., 180 n. 15)
Here is figure 3 referenced
above (Taken from ibid., 178):
Here is a scan of John Baines, Fecundity Figures: Egyptian Personification and the Iconology of a Genre (England: Aris & Phillips LTD, 1985), 118-21, as referenced above, too (click to enlarge):