Gender manifests in everything on all planes, but it would be beneficial at this time to clearly define the context of Gender relevent to this discussion. The word "Gender" is derived from the Latin root meaning "to beget, to procreate, to generate, to create, to produce", it has a far broader and more general meaning than the word "sex" which refers to the physical distinctions between male and female living things, the latter, I think, being what Mikey refers to above, and agreed that in that context, there is no distinctions between sexes in the Afterlife.
Consider the workings of attraction and repulsion, positive and negative, gravitation, love and hate, all manifestations of Gender.
Moving onto Mental Gender, or the idea of Dual Mind, subjective or objective, active or passive, conscious or sub-conscious, voluntary or involuntary is also a manifestation of Gender
The "I" is the masculine, the will, the directive.
The "Me" is the feminine, the creative, the imaginative.
While independent, they are also dependent on each other to function, and one without the other become inert.