This is...an interesting take on what it would mean to have more than two genders. But I think it sort of points out the reason why all animals known to reproduce sexually (with more than one parent, as opposed to asexually, where there is only one parent) only have two genders.
It’s complicated. It’s overly complicated. If any one of the five genders is not present, no children can be had. What happens if, back in their more primitive days, a natural disaster happens to a village and a third of their population dies, resulting in an entire gender being killed off? The result is the population no longer pro creates, and dies.
In the same village with only two genders, where the females, being the ones necessary to carry and deliver the next generation, are protected vigorously, and the males, being larger and stronger but ultimately expendable, defend and protect them, you wind up with more women than men (because men do all the dangerous work), and therefore have over 50% being women, and so if that natural disaster comes and kills a third of the population, you have a very, very large chance of many women surviving and at least one man. A single man of any age in a village of women can restart the population in as little as one generation.
Having more than 2 sexual genders required for procreation almost ensures the species would die out early. Now, you sort of handle that with them having such large litters at a time. But I’d imagine on their home world, they’d have been in a situation where they were more like prey animals or something, with high mortality rates, which would necessitate such high number of offspring. I assume they have these litters often, as their entire society is about getting it on. Without a high mortality rate, your looking at population growth so fast as to be unsustainable. Assuming equal ratio of birth of all five genders, and if they have a litter every year for just five years, then 5 becomes 155 in five years, with 150 of them being under the age of 5 and only 5 parents. Give it 20 years, and if all 150 split into families of 5 and have five litters, then 5 years later there are 930 under the age of five. That’s after only 25 years from one family having offspring. That’s 186 family units. 25 years later, you have an additional 5,580 kids. 25 years later that becomes 33,480 kids. Then 200,880. Then 1,205,280. Then 7,231,680.
In 200 years, a single family unit goes from 5 people to over 200 Million. Now, if you have a planet full of these things? With millions of families? Each of those families would number 200 Million in 200 years. Even starting with 1,000 families, you reach 200 Billion in 200 years. Humans went from roughly a billion all told 200 years ago to 7 billion now, and most of that in the last fifty years. If these things were at 1 Billion 200 years ago, they would have 100,000,000,000,000,000 members. That’s 1 septendecillion.
They’re worse than rabbits, and would fill a world in just a few generations if they had no checks in place. Once they reached a technological level where they could defeat whatever it is that used to keep their population in check, they would spread throughout the galaxy like a virus.
Which, by the way, is the story of the Krogan race in Mass Effect.
On a side note, one thing I have learned is if something is worth doing it is worth doing right. If you do not want people to focus on the grammar and spelling of something you have put your time and effort into, make sure there are no such issues before you post it for all to see. It is natural to want to show off your work as soon as it is ready, but nobody will see the work through its flaws. I’m not saying this as a put down, I’m saying it as a fellow writer who has gone through this kind of deal before. Never, never, never post a first draft anywhere. Never. Rule of thumb is to only ever post final drafts. Your work should be polished and shining, error free. Let someone else proofread, and don’t get discouraged when they sent it back to you covered in red correction marks. This is how a writer gets better. Sometimes we can’t see the problems with our own works until someone else points them out. This is ok. The good thing about writing mistakes is that a quick edit will fix them.