I would say that the apparent androgeny of the angels was not intended by Rublev, from what I read concerning this particular icon and in the general vein of sacred art in that time period as a whole. Orthodox iconography had fairly rigid rules regarding depictions of angels- angels are genderless, but to be depicted they have to be depicted in some form of gender. They can’t be depicted as grown men with beards, nor as female- thus beardless males youth are the required norm for Orthodox iconography, from what I have read. This beardless male youth thus serves as a way of depicting the non-gendered-ness of angels.

The difficulty in distinguishing genders in mediated partially culturally, (because in near eastern cultures men normally have large amounts of facial hair) and partially because of Rublev’s style- he like to use soft lines. and so facial features are not extremely well pronounced. To be sure, he has specific facial hair features for Christ, John The Baptist, the Apostles, etc. However, if one looks closely at some of his other icons in which angels are depicted, there is a distinct means of presenting them. They have the wings, the halo, the same facial features, the braided hair, and this is consistent from Michael to Gabriel to the angels witnessing Christ’s baptism to the Trinity icon.

One thing I stumbled across is that instead of seeing the Father on the left, the Father may be on the right. The Son is spoken of as sitting at the right hand of the Father, and the right hand figure is dressed in blue and green- blue representing sky and thus transcendence; green representing life and thus the Father is source of life. The house behind the left angel could represent the church; thus, the Spirit is the one who builds the church.

Anyway, those are some of my thoughts. Thanks for the post!