Ei, uovo, oeuf, ou, æg, ubh, ŵy are pleasing mono or disyllabic words that suit the oval cosiness of an egg. Even the rounded letters 

e, g, o, u 
look like a clutch that's been laid on the page by a tiny bird. 
Eggs are feminine - not only in their biological relationship to reproduction, but symbolically, as smooth garments for soft, potential life. Indeed, clothing is an apt metaphor for the appeal and femininity of the egg, for, in Italian a poached egg is  'in its shirt' uovo in camicia, and in French 'in a pocket' oeuf poché.