Interesting take on the whole thing:
http://browse.deviantart.com/?qh=§i ... n#/d3kebgs
I'm going to copy and paste what this guy wrote about his picture. Seems like he put a lot of thought into it.
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Reproduction: Perhaps the most controversial of all of the required criteria among Transformers fans. Within the canon, Transformers have been established to have multiple means of producing new life. These include construced bodies and/or protoforms imbued with a Spark (from The Matrix, Vector Sigma, the Allspark, etc.), budding, and even evidence of sexual reproduction through the union of male and female.
Many fans believe that "because Transformers are 'robots', they cannot reproduce, they cannot mate and bear offspring, they have to be built, just like Earth robots." What these fans fail to take into account, it that Transformers are not Earth robots, and not limited by our current level of robotic technology. They are living organisms, bound by the laws of biology. Their bodies are made up of self-replicating nanomachine cells containing cybernetic DNA. They're male and female, they seek out mates among the opposite sex, they even marry, and have been shown, in various canon sources, to have children from these unions.
It was only Marvel comics which ever established Transformers as genderless—with no females at all— and even there they could reproduce through the asexual process of budding. If, in the one continuity where they were indeed sexless, they could reproduce asexually, then, it stands to reason, that in all of the continuities where they are male and female, they can reproduce sexually. This is backed up by the numerous Transformer families we see in the canon. The only thing we never see is the actual act of mating. We don't even see Spike and Carly mate and yet we know Daniel was conceived through their union. There is no reason for it to be any different with Transformers, just because they're "robots". There is more evidence of Transformer sexual reproduction than there is human sexual reproduction within the canon.
This is my theory on the matter based upon what little we know in canon and the inherent limitations of their physiology and necessities of transformation, as well as real world biology:
The male reproductive system consists of a tank which produces and contains the male's cyber-spermatozoa. These contain a randomized mix of half of the male's genes as well as a small amount of Spark energy—the Spark is suffused throughout every cell in a Cybertronian's body (see MtMtE #8). Leading from this reservoir are tubing and pipes which connect to the main reproductive interface. Also connected to this main line are lines from the liquid waste receptacle similar to mammalian males, but likely taking the form of a retractable line and cables capped with a nozzle-like jack, not a phallus (See Bumblebee from the 2007 movie when he "lubricated" on Agent Simmons). This is all protected by the male's retractible "cod plate". Males constantly produce cyber-spermatozoa over the course of their adult lives.
The female reproductive system consists of a rigid ovoid reproductive/gestation chamber located in the lower abdomen and pelvic girdle between the hip mechanisms thus necessitating proportionately wider hips than males. At the top of this chamber are two ovarian nodes in which maturing cyber-ova develop before being released (usually one at a time) into the chamber for fertilization. At the bottom of the chamber is the interface port which is embedded in the seam of the two retractable "birth plates". These are all protected by the female's pelvic armor, which also has a seam running along the center-line that opens to facilitate interfacing or birth. There is no "vagina" and the gestation chamber does not expand during pregnancy. It is of a fixed size. The female only has a limited number of cyber-ova, limiting the number of offspring she can bear over the course of her reproductive life. The exact length and frequency of her fertility cycle, and whether it is a menstrual cycle, estrus cycle, or something else entirely is up for debate, as is whether she ceases to be fertile in her advanced years (as with Humans) or not (as with many other animals).
Power leads in the tip of the male interface jack and female interface port are extremely sensitive erogenous zones.
When interfacing, the male plugs his interface jack into the female's interface port, initiating an energy build-up culminating in the release of the male's cyber-spermatozoa directly into the female's reproductive chamber where they race to link with any potential mature cyber-ova that may have been released by the female's ovarian nodes into the chamber. Should one be present, one of the Cyber-spermatozoa merges with it, initiating gestation during which the genes and Spark energies within each, merge forming a complete zygote which develops within the gestation chamber over time into a new baby.
After gestation is complete, the female's pelvic armor opens, and the birth plates retract allowing the offspring to be removed from the gestation chamber. Given the fixed size of the female's gestation chamber her offspring would, by necessity be very small in relation to her. The infant would grow relatively quickly (though how quick has not been established) being nursed on an energon-rich "milk"—made up of metals and other minerals and nutrients dissolved in an energon solution—produced by the mother's Energomammary synthesizers—until fully weaned between the equivalent ages of human one to two year old, when they start eating "solid" foods.
The exact length of time for each stage of development—Gestation, infancy, toddler, childhood, pre-pubescence, adolescence, adulthood) is undetermined, but canon sources suggest it is significantly longer than that of humans, given that they live for millions, if not tens or hundreds of millions of years (the oldest known Transformers are the lesser gods known as the Original Thirteen Primes, including Alpha Trion and Vector Prime, who have lived for over ten billion years). As Optimus told Raf in TF Prime, Cybertronian life cycles are far longer than that of humans. How much longer is the question.
This is a diagram of the internal anatomy of male and female Cybertronians, detailing all of their major internal systems, including the reproductive systems, as I envision them.
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Some things I like about this guy's theory.
1. Yeah, it's more down and dirty, but spark mingling as a theory of reproduction seems to be too problematic. This gets the job done without having to quantify where sparks come from or how they get there. Leaves a bit of mystery for that.
2. Spark mingling would seem to indicate that 2 males or 2 females could conceive together, which again kind of defeats the purpose of having 2 sexes.
3. The rigid gestation chamber does away with imagery of big bellied, pregnant fembots.
I'm tempted to copy and paste the artists' comments from the reply section here too. The guy definitely did his research. Instead, I'd recommend that if you're interested, just read through the comments section on his pic. They have a discussion much like what we're doing here.