Wesker was selected vecause his parents had a "superior" genetic makeup. If Jake's mother doesn't have those genes, then Jake wouldn't be very interesting for the project at that time. Wesker was much more important. Things would only change after Wesker's survival to the prototype virus.
However, I still think it wouldn't be possible for Spencer to control all of Wesker's personal life.
Yes but even having "half" of the "superior" genetic makeup would make Jake important.
RE6 even confirms this when it is said that Jake carries a very special type of blood.
That alone should warrant at least a moderate interest from Spencer to have at least alluded to someone who was the son of one of his Wesker children.
No matter how anyone tries to reason it, there is just no believable way to look at this other than a asspull in my honest opinion.