Or How Mogwai Get it On
Well, kiddies, you're getting older, hair is appearing in funny places, and it looks like it's time to sit down and have a special talk about the birds and the bees and the mogwai. It's not that difficult really. Birds... eggs. Bees... eggs. Mogwai... spills. Mogwai unlike other mammals don not need wine, candle light, Barry White, or even another partner to reproduce. They just needs water, and pretty much any old spill would do. These little creatures, somewhat like monkeys with Williams syndrome, apparently do not need sex to reproduce. Mogwai are perhaps the only mammal known to reproduce asexually if they are, in fact, mammals and not a creatures of magic and ancient Chinese secrets. Their gremlin form would also lead us to believe that they're a reptile, which further promotes asexual reproduction.

Is there a Promise Ring for Bathing?
Parthenogenesis Mogwai Reproduction
With no other viable mogwai mates around Gizmo has the ability to reproduce asexually, a trait common in reptiles, sharks, and Jurassic Park movies (actually those dinosaurs were trannies, never mind). This is called Parthenogenesis, which is a process in which an unfertilized egg develops into a new individual. Gizmo could come from two mogwai parents, the nuclear mogwai family being the reason for Gizmo's sweet disposition, and his own offspring being nasty little mutants.
First thing's first, Gizmo, Stripe, Mohawk, and Brain were all chicks. This is how most asexual reproduction works. Certain genetic variables do make it possible for males to be produced by females during asexual reproduction, however, these males would not be able to reproduce asexually. Perhaps, there were males and females mixed in the batch, and only the females would posses the ability to multiple. So, the gremlin that drank all that estrogen in Gremlins 2 probably didn't become female, but became a super female (An interesting side note: the super gremlin female had sex with none other than Robert Picardo, but don't tell Picardo's people that because they will get angry... he's a family man).
With parthenogenesis, water then becomes more of a trigger than part of the mating process in gremlin birth. Chemical or electrical stimuli have been used to cause parthenogenesis in scientific studies. This is what happens to mogwai. Perhaps, mogwai and gremlins have a natural allergy to water that creates a negative external stimuli, which causes asexual reproduction to occur. It is possible to be allergic to water, but if that's the case how come is there not a tsunami of mogwai whenever it rains? We've seen tap water and pool water caused Mogwai's to multiple, perhaps it isn't water that mowgai are allergic to but fluoride, common in modern water treatment.
Also, parthenogenesis reproduction is not cloning, while the cells do replicate from a single genetic parent, it's more of a mutation than an exact copy. That's why most of Gizmo's offspring have severe learning disabilities. And Gizmo wasn't really a good dad either (or mom as the case may be), he never once played catch with Stripe or told him that he loved him. No wonder the gremlins ended up being so emotionally disturbed after being raised by a deadbeat dad like Gizmo.
Follow up:
Gizmo has Sexy Hair
My second theory of gremlin reproduction is a a tad grosser. It's typical sperm and egg reproduction, just not from the usual sources. Mogwai are females born covered in sperm, the embryonic fluid contains freeze dried spermatozoon, which becomes matted into the fur. The water than transfers the sperm into dormant mogwaian eggs at the end of every hair follicle. The sperm simply travels through the shaft of a hair follicle and impregnates an egg resting in the hair bulb. The mogwai baby rapidly matures and pops out of a pore much like a pimple.
So, any sort of liquid that causes the sperm to be absorbed into the hair follicle can be the catalyst for mogwai reproduce. It shouldn't need to be water, anything wet should do. The only limitation is the amount of fluid, the amount sperm left in the fur, and the amount of eggs attached to hair follicles. Millions to even a billion of offspring would be possible.
However, there are complications with this theory with the more reptilian gremlin form. No hair means no multiplying.
For further reading, see the process of Mogwai to Gremlin metamorphosis.
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