Imanol de Tafalla wrote...
I would like to add that the biotic abilities in the Asari were the result of genetic modifications made by the Protheans. The ability to meld could have resulted from Prothean intervention, which would tie in to your statement about male births being a rare occuence. Giving the Asari the ability to meld would render males obsolete and increase the birth rate of the Asari population.
Interesting point, and I'll raise you this: who's to say that the lack of male asari in present day isn't the result of Prothean tampering? According to the wiki of ME, the "genetic defect" of an Ardat-Yakshi is present in as much as 1% of the asari population, implying that at one point, the Ardat-Yakshi were capable of mating. If the traits leading to the creation of an AY were a true genetic defect, I would imagine that at least 45,000 years of nothing but pureblood mating (their only recourse after the Protheans cut their ties as their cycle ended until the asari encountered the salarians) would drive that number much higher. If not, why has this trait not died out by now if the carriers of these genetic traits are sterile by nature?
This leads me to another idea regarding why the hypothesized neanderthal asari male is no longer: The asari are the victims of an aborted Prothean uplift, and the Ardat-Yakshi are a subset afflicted with a 50,000 year-long Prothean version of the genophage.
One possible way this could go: During the Prothean observation of the asari, just before the Reaper invasion, the Protheans noticed the males of the species, while much rarer than the females, had certain traits that were deemed valuable to the Protheans. Perhaps it was a vast amount of talent with biotics, perhaps it was the ability to mentally unify and coordinate females through their version of enthrallment, or perhaps due to their circumstances of birth, it could have been an immunity or strong resistance to mental domination themselves. After all, if both parents were what would be known as Ardat-Yakshi, survival to term would require some protection from their mother's overwhelming mental link. Whatever it was, it sparked the Protheans' interest, enough for the Protheans to consider the idea of intervening directly with the development of the asari, doing what they could to accelerate the process with minimal harm. It stands to reason, considering Javik's dismissive and condescending treatment of Liara in ME3, that if the asari had nothing to offer the Protheans, they wouldn't have expended so much effort to advance the asari civilization; aside from protecting a garden world from outside threats, they would have simply waited until the asari died off or developed their civilization enough to induct them into the empire as a servant race.
Anyway, continuing with the speculative history, the invasion of the Reapers changed the Prothean point of view, especially as the Protheans watched their vast imperial fleets and ground forces slowly get chewed up and worn down in their war of attrition, an attempt at an impromptu uplift was conceived. The Protheans would make contact with the primitive asari, and with the right approach, convince the males that their homeworld and all who lived on it were in danger due to a monstrous, ancient evil, and offer them the opportunity to fight for all they held dear.
The primitives, in awe of their otherworldly and sophisticated guests they mistook for gods, in hearing this sales pitch, leapt at the chance, and a compact was drawn up. The asari, in exchange for basic Prothean teachings, would lend their most powerful to the Prothean war effort, and after the war concluded, the Protheans would finish the job of the asari uplift, advancing their civilization until they were ready for induction into the empire. So, the strongest and most capable of the asari (composed mostly of either Ardat-Yakshi progenitors or males) were gathered up, and with a crash course in Prothean warfare, were shipped to the front lines to fight.
All went well until indoctrinated Prothean agents, noticing the recent additions to the battlefront (as well as their formidable approach to Reaper forces) began to let slip to them that the Protheans weren't being completely honest with them; that the Protheans had no intention of fulfilling their word, that the Protheans were simply using the asari, and that the asari would make only slaves to the Prothean empire. These rumors and snippets of gossip shook the asari forces' belief in the Protheans, but didn't break it. At least, not until they saw the advance of the Reapers through the Athena Nebula via scout ship readings, saw them approach Thessia...and keep moving past. Having been entrenched in the Protheans' war for decades now, seeing the mounting numbers of asari casualties, only to find that the enemy didn't care if they lived, and that their gods, so wondrous and beneficent before, didn't care if they died, the incensed primitives took the only course of action they knew would hurt their users: they refused to fight.
When the Protheans learned of the asari defiance, knowing the consequences this would have not only on the war effort, but their other servant races if word of this got out, met the asari protest with brute force, decimating the core resistance with orbital bombardment strikes against the dissenters. Their message was clear: fight, or die. Presented with this answer, the asari dissent turned quickly into ill-fated rebellion, with only a handful of asari troops surviving the infighting. The remaining few were quickly executed for their brothers' and sisters' crimes.
The rebellion had been put down, but the Protheans still had the problem that the asari primitives on Thessia had not upheld their end of the compact. The Protheans would not let this stand, and they sent a communication back to Thessia, detailing how the enemy poisoned the minds of those they sent, and how willingly their fighters took to betrayal, painting what was a force outraged at being manipulated so callously into a cadre of power-hungry, amoral opportunists, eager to betray not only their generous and kind gods, but their own people. It was a masterstroke of wartime propaganda, and the asari still on Thessia ate it up eagerly, going so far as to ending with the asari begging the Protheans to ensure that those...demons... could not appear in their midst again. And the Protheans, while strained due to the war effort, were all too happy to oblige them.
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ANYWAY...that's what I've got.