User blog comment:BunsenH/Ghazt stats 1/@comment-7326455-20140519035357/@comment-24577221-20140519161839

My highest priorities to keep variables constant were the parents' level and happiness. It was only after the project was well under way that it occurred to me that player level might make a difference as well, so from that point I made sure that that was kept constant (and as low as possible, so it might be changed later for those games).

From the point of view of the game designers, it makes sense to give players a little taste of the possibilities to get them "hooked" and then make things more difficult, to encourage them to spend real money. So: it's reasonable for the breeding probabilities to be affected by things like monster happiness and player level... though from that premise, the logical result would be that the breeding probabilities would decrease with higher monster level and/or player level.

The breeding probabilities are so low that it's not really possible for players to experiment with the variables, so I don't think it's likely to be a real part of game strategy. But it's remotely possible that the programmers have slipped in something as a kind of weird joke.