INDIFFERENT ORIGINS. “Males often retain relics of their ‘female’ (technically, indifferent) origins, just as females may retain remnants of structures that arise in early embryos and later become male features. Thus many non-functional developmental ‘vestiges’ relate to sex differences and sexual development.”
https://evolution-outreach.springeropen.com/articles/10.1186/s12052-014-0012-5