Amulets of change shuffle your stats the same as polymorphing into your own race, without risk of a system shock. Possibly, the stat-shuffling process should be a bit more limited primarily to attributes; it probably shouldn’t affect experience level (and thus HP, Pw, or skills), reset your nutrition, or cure most illnesses like a self-polymorph would.

Amulets of change don’t disintegrate when you put them on; instead they autocurse. Once you remove the curse and take off the amulet, your original gender is restored.

Amulets of change generate cursed no more than regular amulets (it no longer generates cursed 90.5% of the time).

Same-sex foocubi will use an amulet of change on themselves as an offensive item.