In the Stars.

Introduction

Long ago only two genders used to exist, but there was a sudden decline in the human population making it so that the people were scarce to find throughout the Earth. As time went on the Human race began to adapt, and the only difference between male and female were the outward appearance. 

All humans became capable of bearing a child. 

Alpha:

The Alpha is known as the more dominant of the genders. The Alpha is very assertive and tends to only seek out female Alpha's if they want a strong family. If the Alpha is wanting their fated pair with an Omega they have to chose wisely. Once they claim (or mark) the Omega they must then care for that Omega. Alpha's are able to have more than one partner, though it is looked down upon unless it is equally accepted with all partners.

The Alpha has a 'knot' that they insert into their partner to ensure pregnancy. Their 'ruts' are somewhat similar to the Omegan 'heat' but they do not have periods of the month in which this 'rut' is activated. They are more controlled by the Omega's around them and do not inhibit their work. During this time of 'heat', the alpha will ejaculate more semen than any other gender. The pheromones that an Alpha cares depends on the Alpha, but they usual insert fear and a sense of obedience into the Omega affected. 

Jobs of an alpha: Piolet, doctor, corperate boss, etc.

Beta:

Beta's make up more of the population than any other gender. Beta's are able to bear children but for male beta's it is the hardest to get pregnant without medical help. Beta's usually end up marrying other beta's but in rare cases, they will be found with an Omega or a very assertive Alpha. 

Beta's do not have a 'knot' but are able to impregnate an Omega (but it is very difficult to do so). Unlike the Omega's they can even reach the same rank as an Alpha in the workforce. Beta's do not experience Estrus, which is the intense 'heat' known to many Omega's. The Beta can contain themselves around an Omega and are not easily influence by the pheromones that an Omega can spread during their 'heat'. 

Jobs of a Beta: Any.

Omega:

To most, Omega's are seen as useless sex machines that only whore around and have children. In many solar systems, Omega's are killed the second their gender is found out (which is around 13).

Omega's experience a period of Estrus, or 'Heat', that lasts for seven days every month. There is a rare chance for the omega to become pregnant when not in that time of 'heat', but it is possible. Also, it depends on the Omega how intense the heat is, the variations of duration, and the smell of their pheromones. A normal Omega can not work through a heat so more than likely they will take suppressants to stifle their heat. Most Omega's are not found out on earth and tend to be thought of as Beta's because of the suppressants.

Most Omega's tend to wear collars during high school and college if they are not tied to anyone at this point. Some Omega's don't even end up going to college because of the ridicule an untied Omega will receive (being asked what wrong with them for not being tied yet). The collar is to prevent an Alpha from marking or scenting them without the Omega's consent. The mark is in the form of a bite that is usually at the back of the neck, and once an Alpha or Beta mark the Omega it is impossible for that Omega to have sex with any other person. In one case the Omega's heart rate increased and the Omega died from a heart attack because the partner was not their Alpha. 

Even if they do not like the Alpha that gave them the mark, they are tied to that Alpha for life. 

In each of the three gender, there are what is called, a middle-class gender. A middle-class gender is just a more specified gender assigned to the pheromones and the fertilization that the man or woman have. The middle-class genders are: Alpha Alpha, which is the highest Alpha and the most successful Alpha at insemination but also the most violent when it comes to a rut; Beta Alpha and Alpha Beta, these two are very similar to each other and very hard to differentiate, they are more successful than most because their anger doesn't get to them but they are not considered the best when it comes to insemination (the only difference between the two is that the Beta Alpha has a knot at the base of his penis unlike the Alpha Beta); Beta Beta is the most neutral gender, them being very handy in all crafts, but sadly Beta Beta are usually born infertile; Omegan Beta is found to be the most feminine of the Beta's and is some cases are able to bear Alpha children; Alpha Omega, an Omega who refuses to be bonded to an Alpha and tends to live alone thinking that they are fine with only their suppressants (but to some, their heat can get the better of them); Beta Omega, the middle Omega who can tend to live a normal Beta life without being found out that they are an Omega nor having to be marked unless they wish to be; and Omega Omega, who is impossible to not be found out (Omega Omega's are the most feminine of the genders and find themselves enthralling even Beta's to fall into ruts around them because their heats are so intense. They are the most threatening Omega, but also the most vulnerable).