The Hu-V24 is an extremely virile virus which infects non-human, anthro hosts and transforms them into an human ethnic type.

In this case, Japanese.

Thankfully there is a vaccine for it but it only has 35% effectiveness and requires upping with boosters to get better coverage. Becky was very out of date and as well was "too busy" to go re-up.

Conspiracy theory abounds as to where Hu-V24 came from, any suggestion that the Japanese government might have engineered to help their population issue are silly and should be disregarded.

More so that all exposed to the Hu-v24 are turned into fertile breeding examples of age 35 gain normative straight sexuality if they are not is also a conspiracy, remember to report anyone implying such theories.