An alien creature has secretly landed on earth, seeking to propagate itself among the local species. It studies the individual sexes of a race called humans and determined that the males would be more suited for the purpose. They produce millions of genetic material a day involuntarily with little recovery time, making them a perfect factory for making more of creatures like itself. They are also wired to desire to spread their material, making them easily influenced by certain methods (allegedly).
After taking control of one individual, it soon realizes that it has access to a faster method. Unlike the medieval past, where demons had to take control of humans to pass on progeny one by one, technology as developed to the point where this can be done far easier through the use of sperm banks. These locations store genetic material from donating males, keeping them in storage for long term use to keep them applicable. It determined that it can use this as a way to spread itself to potentially billions of people, creating children all across the world for more quicker and easier than before. These children would operate as a hive mind, providing fresh bodies for the creature to possess if it is ever killed.
The creature cannot fully possess the human, as doing that would change the victim biologically and be a clue that something was wrong. It decides to remain dormant and allow the human to retain its form. However, I need the sperm material of the human to be the genetic material of the creature itself when held under scrutiny. This 👽 sperm will be able to "hijack" eggs through biological story-plot shenanigans, converting the sperm and egg combination into an alien embryo.
Plot holes aside, would it be possible for a human male to biologically produce sperm for another species ? How can I make this work?