Earth-4433 (Open)

This alternate earth has 4 biological genders: Arel (masculine body frame with male sex organs), Arella (masculine body frame with female sex organs), Emon (feminine body frame with male sex organs), and Emari (feminine body frame with female sex organs).

Procreation still requires a PIV intercourse, and offspring will always match the parents (ie, two masculine parents will produce masculine children, an arella/emon pair will produce other arellas and emons, etc.)

There are no menstrual cycles on Earth-4433; instead, egg carriers go through extreme estrus (Heat) cycles on the same monthly schedule, during which, they will experience elevated arousal and need for sex that intensifies every day they don't have PIV intercourse. The cycle can ONLY be halted with by intercourse, and what is normally 3-6 day period, can become feral desperation on day 7, 8, and beyond, if they don't have sex. Sex that halts a heat cycle is called 'grounding.'

Meanwhile, Arels & Emons have their own hormonal cycle too, called Tenesol, or more commonly known as the “Ice Cycle.” As periods (or Estrus on Earth-4433) run every 28 days, Ice runs every 30-33 days, and is also a result of lack of sex; this results in drastic mood swings and affects each arel or emon differently, ranging from lethargy and irritability, to depression and anger. Like heat, symptoms deepen for each ‘ice cycle’ that is not acted upon, which could lead to extreme results. Sex that halts an ice cycle is called 'resetting.'

Anything that hasn't been mentioned is can likely be assumed to be the same as our world. I'm looking forward to seeing what you all write.