So reading Bat's posts again:
So if I had to guess, interactions increase some sort of luck quotient and neglect decreases it. Every time there's an update, there's a chance any given Ryu will evolve, but the value of the chance is based on how much luck the Ryu has. So if more care = more luck, then let's get eyes open. Also probably worth considering how active the parent is because more active means the Ryu is more likely to be seen, even if born a little later.