We are to presume that Palpatine caused Anakin to be born via Force manipulation
Wait, what?
Anakin being 'born off the Force' is canon, IIRC. He has no father. I think I recall Shmi Skywalker telling Qui-Gon as much? Either in the SW1 movie or the novelisation.
What isn't clear in canon is the how and they why of it, but there's sort of a 'semi-canon theory' about that:
There's a scene from Revenge of the Sith, the opera scene, when Palpatine is talking about a Sith who could control life and death and who was murdered by his apprentice, Sidious. There's a long standing fan theory that Sidious continued his master's work and manipulated the midiclorians to create Anakin as part of his long term scheme to become Emperor.
Methinks that's a bit more than a fan-theory: It's described in more detail in James Luceno's novel
'Darth Plagueis' (Palpatine's master & predecessor). However, while the novel (and the retcons) is pretty good, like most of Luceno's stuff, it was never considered canon, even before Disney took over.
As the novel comes to a close during the events of The Phantom Menace, Sidious and Plagueis learn that a young boy named Anakin Skywalker, a former slave found by Qui-Gon Jinn on Tatooine, had been born of the Force. They discern that this is most likely due to Plagueis's experiment of creating life through the Force, which he had commenced about a decade earlier.
http://starwars.wikia.com/wiki/Darth_Plagueis_(novel)
Note though that there's no indication in the novel of either Plagueis or Palpatine creating Anakin
deliberately - if I remember the novel correctly, Plagueis and Palpatine undertake several (extremely 'high-powered') Force-experiments (either as part of Plagueis' quest for eternal life and/or their 'un-balancing' the Force in preparation for the culmination of the Millennia-old plan of Sith takeover), and once they learn of Anakin's birth, Palpatine
suspects that the Force created Anakin as a reaction to those experiments.
IIRC, he's actually more than a little bit unsettled by that, since it would indicate that the Force can act on its own, and
very specifically so, without control by a Force-user, which would obviously be bad news for a Force-user striving for complete control and domination of both the Force and the Galaxy. Remember how much emphasis Palpatine placed on Force-vision and Force domination to further his aims - it'd be like a chess player discovering that the rooks are sentient.
I think that's a theme that Luceno comes back to several times in other novels ('The Unified Force') as a major philosophical difference within the Jedi and Sith orders: Sith see the Force as something to be used, Jedi see the Force as something to be guided by, but neither is entirely sure whether the Force might not an entity with its own goals, that can act independently of either.
All of that non-exactly-canon: Luceno is probably the best retconer amongst the EU-authors ('The Unified Force', 'Millenium Falcon'), but I guess the powers that be were wary of tying that bit of lore down in to much detail.