I think the further away you go from human qualities, you lose broad appeal. People tend to prefer things they can relate to, which is why depictions of aliens tend to be anthropomorphic with two eyes, a mouth and standing upright. Yeah, you can go wildly in a different unconventional direction, but it becomes harder to form an emotional connection with, and the interest narrows itself. The Xenomorphs are somewhat of an exception to this.

Ah, that's very true! If you go too crazy with your ideas, people can't relate to it anymore.

Exactly, unless that is your point. If you're trying to create the idea of a shambling monstrous alien that has bizarre reproduction methods, it would make for a great movie-monster type setup. Beyond that, it's a tough sell to all but a niche sci-fi audience. So it really depends on the goal and intention :)

I'm working on a world with anthromorphic critters and thought it would be an interessting idea to turn that aspect of them upside-down.
There are also humans in there, so it's not like there is nothing the reader could ever relate to, but I also want them to relate with the other species, as they are mostly good-natured sentinents, unlike the xenomorphs.

I feel if you took the alien/creature with unusual reproduction methods and flanked it with other human-like characteristics (sense of clear emotions, clear sentience, a duty/purpose) or other characters in the universe that interact with it on an emotional level, you could pull it off! It would give the audience a way to connect with it other than seeing it as an abomination.

I would find it very interessting to break or put a twist on the whole "penis enters vagina to insert semen and fertile egg" idea.
For example, I think it's very interessting that female hyenas have such weird and special genitalia in comparison to other female mammalians. It's really unique, and probably a product of their matriachial society.

This sounds really fucking awesome. Excuse my language, but I just beamed with how fun of a concept that would be to play with. To me, I think the keyword when trying to figure out a practical and believable way to bend the "sperm/egg/fertilize" idea is efficiency. What could possibly be more efficient?

Asexual reproduction is actually more efficent haha. The whole sexual reproduction banks on the 'lottery' system and it's a lot more effort than simply splitting in half, as I recently learned when looking into the whole big mess that reproduction is.

But I guess just splitting in half is not something an organism made of many complex cells usually does.

Imagine, though - you live on a planet where another, humanoid-species does exactly that. You walk in on your alien rommate one morning only to find two of them.

"Shit Jared, is that your twin?"

"No, that's just a copy of myself, I thought it was about time to start a heritage of my own. Meet my child, Jared 2."

And to play on that fun idea, a lot of the phenotype variation can occur through different environmental adoptions! So you're not simply getting copies of the same thing, but the environmental conditions change each person for suvivability purposes, which in turn passes that to it's "progeny" as it splits itself. Maybe there's a hard limit to how many times a subject can perform a split, so doing it in the most effective or safest environments is preferred.

As you said ,reproductive abilities took many many different paths and forms just here on earth.
and that's partially affected by the composition of our world and it's ecosystem. If you were to find a nearly identical earth-like planet, that had similar biological origins, there would still vast differences in reproductive techniques, but some overly. But if you go to a planet that is alien in comparison to earth, you're just going see things we may never have even thought of, but at the same note, you may STILL see some overlap.

Yeah, although I guess since it's a bit of a fantasy setting to begin with, it doesn't necessarily have to follow nature and logic that closely.

oh.... I was thinking about it from a sciencey way... nevermind! xD

I'm trying to make a bit of a mix of both... I like following logic and science, but I don't want to get too invested with following a set of rules, so too say.
Because I'm also a big fan of mysterious things and settings, and the whole 'things are simply like that because'. I mean if you think about it it's kinda mind boggling that we live on some planet that compared to the rest of the (ever expanding) universe is not even the size of a speckle of dust on your bookshelf.
A bit of mystery can be just as realistic, in a way.

While I wholeheartedly agree with Struggler, I also enjoy some warped creativity and a lot of guts in my artists. I'm not exactly conventional with my tastes when it comes down to statistics, so you'd be asking the wrong guy if you wanted to make something that's appealing to most people, but I certainly would be loving to see something like this.

Totally agree with this. It's a topic with a lot of untapped potential for some unique physiology. And this is where the work of H.R. Giger absolutely shines. It's niche, but goddamn it's gorgeous and inspiring, and someone is gonna do it.

Yeah, I just think it could be a small part of setting things apart from the norm.

I sorta think it's intresting how the all female asari reproduce in mass effect where they mind meld to have babu (Albiet I think it's also kinda corny XD)

I still have to play Mass Effect, but since you know the game(s) already; how touched upon is the subject of reproduction? How much weight does it have in the canon and in which detail does it get mentioned?

These are all really good questions and some of them I have been asking myself during developement.

"How long until the offspring matures? What are the requirements for offspring to 'take their time' growing up vs offspring that needs to be mature and fertile in a really short time? How big are the litters - why so many/little?" etc.

And I completely agree @ the environment should fit the species' characteristics, and vice versa!

I have thought about something like that a while ago.
Often forms follows function. Now, while alien worlds can be different, they follow the same natural laws, which in turn could mean, that we have seen most forms that living creatures would take here on earth.

That said, there are still a lot of possibilities of using them in new ways. The parasitic aliens are in principle not so different than some insects that use larger animals to bear their offspring. Only the scale is changed (and some of the details).

Though Struggler is right except for the Xenomorphs. They are not popular because they have great characters, but because they are such great inhuman monsters. Just is the Predator, though he is more relatable.

Of corse ther can always be exceptions.

For example the 'Humanx Commonwealth' from Alan Dean Foster features a insect species called the Thranx. After Humans and Thranx got over how they looked (took a bit of work), they found out they rather liked each other in general and their differences meshed well, leading to them becoming the founders of the Humanx Commonwealth. They combined even better with a new weapons system. One of each species makes the crew of a Stingship. Essentially they use drugs to mentally wake the killer in the Human and make the Thranx more logical. Throw a tactical computer, the Thranx decides when to shoot and the Human does so with the efficiency of a natural predator.
This is just a rough and short description. For more details either search online, read a frew of the novels or try to get the GURPS RPG book of it.

I will look into that, thanks for the suggestion!

And yes, form follows function! There are so many weird ways of reproduction on our planet alone!
Like snails, they are shooting and piercing each other with some sort of sperm-arrow - pretty fierce!!

*nodnod*
BTW, something I haven't seen to often is going into the actual mating habits of animals and how they translate to their furry counterparts. For example how quick felines finish and how often they repeat it. Years ago I read about a lion in a zoo that relieved himself with a tire in his compound so often they removed the tire because they feared he would hurt himself.

Think of it like pollination, reproductive pores.

If you ever want to use this in fiction, don't do the bucket reproduction from Homestuck!
Trolls put... genetic material... in a bucket, the bucket is then taken to a birthgiving mothergrub.
That also makes gender unimprotant for reproduction which is cool.
Problem is when fans of the series imitate this by spiting into a bucket in a public restaurant. Don't.

https://c1.staticflickr.com/7/6009/.....87a5bc58_b.jpg

The chestburster was only one phase in the cycle. Those came from the facehuggers, which came from eggs, which were laid by the queen. I don't think it was ever mentioned how the queen reproduces, though the rest of the cycle seems inspired by colony insects like bees and ants, so if it's not asexual then there's some stage where the queen gets it on with a boy alien somehow. Though as an aside it seems really inefficient to lay only one egg per host given how convoluted and dependent on a host victim it all is.

As to your original question though, it all depends on if you want to do sexy porn or something else. Aside from Aliens-style horror, I'm sure I've seen sexual incompatibility used for humor, though I can't remember any examples offhand. Could be an interesting subject to explore.

Huge post ahead, so first a bit of background, I read a lot and write a little bit so I gave some thought to storytelling, writing concepts and the like.
(I actually had poor Gatogato read a story of mine, haha, though she didn't seem to mind!)
I guess a lot of interesting stuff has already been said but I suppose I can give my general perspective on it too.

I don't believe it's uncreative or lazy to reuse existing concepts - I actually think this is the basis of creativity; people never create in a vacuum, and draw inspiration from a lot different sources, and a lot of what surrounds them, as they should - drawing inspiration from these sources as a base to build on will actually make the resulting concepts stronger, as they will be grounded in a familiar reality.
In my opinion, creativity will make itself visible not in how different (or outlandish) the concepts are, but how the concepts work together.
For instance some people will create characters or concepts with a lot of defining features to set them apart from the others ("hey my species is a rainbow canid with unicorn horn, checkered fur pattern, translucent wings and a horse penis"), but it's not enough to just pile up features to have a design that works well - it just creates clutter.
In fact, it's possible to do a variation on existing or even very common concepts or stories that have been told many times before, but still bring something new or interesting.
Most concepts can be made to work, but a very important point is that there has to be an internal consistency of the universe they're being used in.
Whether it is entirely realistic (hard sci-fi, fiction set in our world), or has some amount of "magical" concepts (fantasy, soft sci-fi, magical realism etc.), the universe has to follow its own, sometimes unspoken rules; this is what makes immersion into the universe possible.
When you introduce a concept, it will have implications for the rest of the universe - due to these rules, the universe has a life of its own, and should "react" mostly according to them - so this leads to a lot of questions.
For instance, why are things this way? Does the setting already hints or logically leads to it? What does the concept leads to for the characters? How does it influence them? What does the story gains from it? What other concepts will it introduce?
A concept that has no meaningful story or universe implications will often feel "forced". It's there, but it doesn't bring anything to the story - and is therefore unnecessary.
Examples of "good", internally-consistent concepts in an "unrealistic" universe:

- Trolls from Terry Pratchett's Discworld novels. They're basically living rocks.
Yeah, living rocks don't exist, but, MAGIC. This is a fantasy universe - the reader is ready to do some suspension of disbelief.
It's no reason to drop logic out of the window though: what does it mean for them to be rocks? Well, their nervous system is sillicon-based. As a consequence, they're prone to overheating, and become stupid or stop moving in heavy sun or heat. Since they often contain precious minerals, other species will want to mine them, etc.
From the logical consequences of the concepts introduced from them, an internally consistent background is being created, and some story threads are already made possible.

- Salman Rushdie's surrealist or dream-like sequences in the Satanic Verses.
While the book's narrative is well-grounded in very realistic themes (immigration, religion, anglo-indo-pakistani culture and history), the two main characters magically survive the explosion of their plane, and their physical bodies actually take semi-divine forms (one becoming the Archangel Gabriel, and the other one the Devil - not much spoilers there, it's right at the beginning of the book).
But even when the magical erupts into the real world, breaking the expectations of the reader, the story still continues to follow its own internal rules - people are still people, and react as such.


Another point to consider is the effect on the potential reader - the author wants to present the concepts in a certain way, but the way they choose to tell it will influence how their message is received.
A common sci-fi trope is indeed to play on the similarities and the differences between alien and humans.
In terms of story, if it turns out an alien has features that set them apart from humans, such as a completely different reproduction method, it will likely create the effect of an irruption of the strange into the familiar for the reader.
This effect will have to be taken into account for the story.
For instance if the author wants to present a species in a positive way, but gives them attributes that will likely be surprising or off-putting to the reader, they will have to find a way to make the reader understand why this is "normal" for them, so that the reader is still able to connect emotionally with them, else it won't work well.
Hard to balance in a story for instance, because you can't just stop and explainwhy this is ok and great, this would break the pacing - you have to tell the story and let the reader make up his own mind.
A dissonance between the message the author wants to convey, and its actual reception by the reader is very bad, writing-wise - it kills the immersion.
Example I've read of such dissonance (in some story I was translating, you can bet I wasn't too happy): author describes character as gentle and fatherly towards female char; character's actions and words give creepy rapist vibes instead. Reader (me) goes "wat". Immersion ruined.

To go back on the subject of alien reproduction: if the concept is consistent with the rest of the universe, and not in contradiction with other parts or rules of it, it can be made to work. What will make it work is how it plays out with the other concepts.
I think it's definitely good to experiment with the concepts you like, and see how they would play out in your universe.
The most compelling stories will stem out from the things and concepts you truly enjoy - passion shows, and it's contagious.

Regarding the other post about asexual reproduction, it is actually possible in some complex species as well.
Parthenogenesis does happen among some lizard species for instance - females being able to produce (female) offspring entirely on their own. Hey tumblr, get a load of these guys! Smash the patriarchy!
Why is sexual reproduction so widely disseminated among species, though? Most likely because it gives a huge evolutionary advantage in terms of genetic variability, and therefore possibilities of adaptation to an environment.
Asexual reproduction leads in many cases to much less variability (main source of it being mutations, or horizontal gene transfer, for instance genetic material being acquired and included from other lifeforms like with bacteria), and the risk the loss of the entire population in case of a change in environment.
As to the probable similarities between alien humanoid species and human species - in evolutionary terms it is rather common for similar organs, behaviours, etc. to be "re-invented" by different species if it gives them an evolutionary advantage.
This is for instance also something to consider if you decide that your concept should follow the laws of evolution as a driving force (not that it has to adhere to it fully, or at all).

TL;DR: every concept can work as long as it's consistent with the rules of its universe; don't be afraid to experiment!

Doesn't seem to mind, doesn't seem to mind, i actually ENJOYED it :D :D :D.

I do think that there might be similarities forced by evolutionary necessity. Sponge or anemone style reproduction is a little too haphazard to really work for sapients. A bird or frog styled cloaca makes a lot of sense - you really really don't want to get too caught up in screwing when something could tear around the corner and try to eat you any moment. But internal fertilization makes a lot of sense too - it ensures that sperm and egg are in really close contact - and then you get into the wide variety of mammalian/avian/reptilian penes. I think once you slap one of those on an alien, it allows for viewer familiarity and you can kinda justify any shape you want to give it.

That's a good point, but there are a few considerations to bear in mind. First off, how did this species arrive at a given means of reproduction? If you're coming up with something new, it's not enough to make it alien; it needs to be logical, and it needs to follow causality. Let's say your alien species reproduces via hair sex: how the crap does that work? What's the advantage? What evolutionary pressure brought us here? It's kind of hard to come up with an excuse for something which is blatantly just there to jump up and down while shouting "look at me! I'm different!"

And then there's the question: is it different? Or is it just familiar monkey business in an oddly shaped wrapper? Is that okay in this given case? For example, in Star Trek VI: The Undiscovered Country, there's a comedic line used after Captain Kirk kicks an alien in the knee, dropping it to the floor in agony: "Not every species keeps their genitals in the same place, Captain." Why would they keep recognizable genitals at all, though? It works in a universe of plasma conduits and phasers, but might not jive with a setting where we have to settle for solar sails and kinetic projectiles.

Bringing us to the big one: why does the audience care? Is it plot-relevant, or just voyeurism? Voyeurism can be okay, provided it doesn't get creepily clinical (unless the plot calls for that). If the story doesn't actually involve reproduction, though, descriptions of the act are pretty much just fetish porn. Larry Niven goes there with his "rishathra," which is essentially just an excuse for characters of varying species to mash their naughty bits together. Not that there's anything wrong with that. On the other hand, in Sherri S. Tepper's novel, Grass, we learn a bit about the latter part of the foxen life cycle, but never really get around to explaining much about the actual reproductive process; the book doesn't suffer for the omission.

tl;dr:
-Does it make sense?
-Is that okay?
-Is it actually different?
-Is that okay?
-Is it plot or porn?
-Is that okay?

Bonus suggestion: Earth is a really, really weird place. Have a look at actual non-fictional species for examples of freaky reproductive cycles, from mind-controlling mushrooms to lizards that cycle physical traits from generation to generation in a game of sexual rock-paper-scissors.