Minecraft mod. This mod has been around since April of 2011!
This mod adds ages and genders to players! Player setting combinations add new hurt sounds, models (body shape) and default textures. Zombies also have genders and textures based on the zombie's age and gender combination. Use this on your server to synchronize all the settings for each player across all connected clients!
This mod is available on CurseForge: https://www.curseforge.com/minecraft/mc-mods/gender